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Chap.?..—. Copyright No. 

Shell/ ^"^ 51^^ 




TESTING MILK 

AND ITS PRODUCTS. 



A MANUAL FOR DAIRY STUDENTS, CREAMERY AND CHEESE- 
FACTORY OPERATORS AND DAIRY FARMERS. 



BY 



/ 



E. H. FARRINGTON and F. W. WOLL 

Professor in ^Charge of Dairy School Asst. Prof, of Agrl. Chemistry 

Of the Uqiversity of Wisconsiq. 



©Uith ^ilu^tvatianft. 



FIRST EDITION. 



madison, wis. 
Mendota Book Company 

1897. 

ALL RIGHTS RESERVE^. 

L 




WO COPIES-RECEIVED 



Copyright, 1897 
By E. H. FARRINGTON and F. W. WOLL 



M. J. Cantwell, Printer 
Madison, Wis. 



PREFACE. 



The present volume is intended for the use of dairj' students, 
creamery and cheese-factory operators, practical dairymen, and 
others interested in the testing or analysis of milk and its prod- 
ucts. The subject has been largely treated in a popular manner; 
accuracy and clearness of statement, and systematic arrangement 
of the subject matter has, however, been constantly kept in mind. 
The aim has been to make the presentation intelligible to students 
with no further training than a common-school education, but 
their work will naturally be greatly lightened by the aid and 
guidance of an able teacher. 

Complete directions for making tests of milk and other dairy 
products are given ; the difficulties which the beginner may meet 
with, are considered in detail, and suggestions offered for avoiding 
them. It is expected that a factory operator or practical dairy- 
man, by exercising ordinary common sense and care, can obtain a 
sufficient knowledge of the subject through a study of the various 
chapters of this book to make tests of milk, cream, etc., even if he 
has had no previous experience in this line. 

For the benefit of advanced dairy students who are somewhat 
familiar with chemistry and chemical operations. Chapter XIV 
has been added giving detailed instruction for the complete chem- 
ical analysis of milk and other dairy products. The detection of 
preservatives and of artificial butter or filled cheese has also been 
treated in this connection. 

As the subject of milk testing is intimately connected with the 
payment for the milk delivered at butter- and cheese factories, and 
with factory dividends, a chapter has been devoted to a discus- 
sion of the various systems of factory book-keeping, and tables 



iv Testing Milk and Its Products. 

greatly facilitating the work of the factory secretary or book 
keeper have been prepared and are included in the Appendix. 

Acknowledgment is due to the following parties for the use of 
electrotypes, viz: Vermont Farm Machine Co., Bellows Falls, Vt.^ 
Cornish, Curtis and Greene Mfg. Co., Fort Atkinson, Wis.; Elgin 
Mfg. Co., Elgin, 111.; F.B. Fargo & Co., Lake Mills, Wis.; DeLaval 
Separator Co., N. Y. City; Henry Troemner, Philadelphia, Pa.; 
Springer Torsion Balance Co., N. Y. City; J. H. Monrad, Win- 
netka. 111.; Borden & Selleck Co., Chicago, 111.; Dairymen's Sup- 
ply Co., Philadelphia, Pa.; and the agricultural experiment sta- 
tions at New Haven, Conn., and Madison, Wis. 
University of Wisconsin, 

Madison, Wis., Oct. 1, 1897. 

E. H. FARRINGTON. 

F. W. WOLL. 



TABLE OF CONTENTS. 



Introduction. Pages^ 

The need of a practical milk- and cream test. 
Introduction of milk tests. Short's test. Other milk 
tests. The Babcock test. Foreign methods. Gerber's 
method. DeLaval butyrometer. Fjord's centrifugal 
cream-test, ----- 1-10* 

Chap. I. Composition of milk and its products. 
Water. Fat. Casein and albumen. Milk sugar 
(lactose). Ash. Other components. Colostrum milk, 11-19^ 

Chap. II. Sampling milk. 

Sweet milk. Partially churned milk. Sour milk. 
Frozen milk, 20-24 

Chap. III. The Babcock test. 

Directions for making the test: Sampling. Add- 
ing acid. Mixing milk and acid. Whirling bottles. Add- 
ing water. Measuring the fat. 

Discussion of the details of the test: 1. Glass- 
ware. Test bottles. Marking test bottles. Cleaning 
test bottles. Pipettes. " Fool pipettes." Acid measures. 
The Swedish acid bottle. Calibration of glassware. Cal- 
ibration with mercury. Cleaning mercury. Calibration 
with water, a. Measuring the water, b. Weighing the 
water. 2. Centrifugal machines. Speed required for the 
complete separation of the fat. Ascertaining the neces- 
sary speed of testers. Hand testers. Power testers. 
3. Sulfuric acid. Testing the strength of the acid. The 
Swedish acid tester. The color of the fat column an 
index to the strength of the acid used. Influence of tem- 
perature on the separation of fat. 4. Water to be used 
in the Babcock test. Reservoir for water. 5. Modifica- 
tions of the Babcock test. The Russian milk test. Bart- 
lett's modification, ..-.----- 25-63'- 



vi Testing Milk and Its Products. 

Chap. IV. Cream testing. Pages. 

Errors of measuring cream. Avoiding errors of 
measuring cream. Cream test bottles. The bulb-necked 
cream bottles. The Winton cream bottle. Use of milk 
test bottle. Use of 5 cc. pipette. Weighing the cream, 64-73 

Chap. T. Babcock test for other milk products. 
Skim milk, butter milk, and whey. The double- 
necked test bottle. The double-sized skim milk bottle. 
Cheese. Condensed milk, 74-79 

Chap. YI. The lactometer and its application. 
The Quevenne lactometer. Influence of tempera- 
ture. N. Y. Board of Health lactometer. Reading the 
lactometer. Time of taking lactometer readings. Cal- 
culation of milk solids. Adulteration of milk. Calcula- 
tion of extent of adulteration. Skimming. Watering. 
Watering and skimming. Other methods of adulteration 80-93 

Chap. YII. Testing the acidity of milk and cream. 
Cause of acidity in milk. Methods of testing 
acidity. Manns' test. Devarda's acidimeter. The alka- 
line tablet test. Acidity of cream. Determination of 
acidity in sour cream. The standard solution used. Spill- 
man's cylinder. Rapid estimation of the acidity of ap- 
parently sweet milk and cream. Detecting preser valine 
in milk. "Alkaline tabs," - 94-110 

Chap. YIII. Testing the purity of milk. 

The Wisconsin curd test. The fermentation test, 111-115 

Chap. IX. Testing milk on the farm. 

Variations in milk of single cow^s. Cause of vari- 
ation in fat content. Number of tests required during a 
period of lactation in testing cows. When to test a cow. 
a. As to quality of milk produced, b. As to quantity of 
milk produced. Curler's method. Record of tests. 
Sampling milk of single cows. Size of test sample. 
Variations in herd milk. Ranges in variations of herd 
milk. Influence of heavy grain feeding on the quality of 
milk. Influence of pasture on the quality of milk. Method 
of improving the quality of milk, 116-133 



Table of Contents. vii 

Chap. X. Composite samples of milk. Pages. 
Methods of taking composite samples, a. Use of 
tin dipper, b. Drip sample, c. Scovell sampling tube. 
One-third sample pipette. Accuracy of the described 
methods of sampling. Preservatives for composite sam- 
ples. Bi-chromate of potash. Other preservatives. Care 
of composite samples. Fallacy of averaging percent- 
ages. A patron's dilemma, 134-14-9 

Chap. XT. Cream testing at cream-gathering 

creameries. 

The space system. The oil test churn. The Bab- 
cock test lor cream. Sampling tube. Sampling cream 
for composite testing, - - 150-159 

Chap. XII. Calculation of butter and cheese 

yields. 

Calculation of yield oi butter: Butter fat test 
and yield of butter. Variations in composition of but- 
ter. Overrun of churn over test. Factors influencing the 
overrun. Calculation of overrun. Conversion factor for 
butter fat. Butter yield from milk of different richness. 
a. Use of butter chart, b. Use of overrun table. Calcu- 
tion of yield of cheese: a. From fat. b. From solids not 
fat and fat. c. From casein and fat, . . - . 160-173 

Chap. XIII. Calculating dividends. 

Calculating dividends at creameries: Proprie- 
tary creameries. Co-operative creameries. Illustrations 
of calculations of dividends. Other systems of payments. 
Paying for butter delivered. Relative value tables. Cal- 
culating dividends at cheese lactones: Proprietary fac- 
tories. Co-operative factories. Illustrations of calcula- 
tions of dividends, 174-185 

Chap. XIY. Chemical analysis of milk and its 

products. 

A. Milk: Specific gravity. Water. Alternate 
method. Fat. Casein and albumen. Van Slyke's method. 
Milk sugar. Ash. Acidity of milk. Detection of preser- 
vatives in milk. Boracic acid. Bi-carbonate of soda. 
Fluorids. Salicylic acid. Formalin. B. Skim milk, but- 



viii Testing Milk and Its Products. 

ter milk and whey. C. Butter. Sampling. Determina- Pages. 
tion of water. Fat. Casein. Ash. Complete analysis 
of butter in the same sample. Detection of artificial but- 
ter. Filtering the butter fat. Specific gravity. Reichert- 
Wollny method (Volatile acids). D. Cheese. Water. 
Fat. Casein. Ash. Other constituents. Detection of 
oleomargarine cheese ("Filled" cheese) - - - - 186-203 

Appendix. 

Table I. Composition of milk and its products. 

Table II. Milk standards. 

Table III. Ouevenne lactometer degrees corres- 
ponding to the scale of N. Y. Board of Health lactome- 
ters. 

Table IV. Correction table for specific gravity 

of milk. 

Table V. Percent of solids not fat, correspond- 
ing to to 6 percent of fat and lactometer readings of 
26 to 36. 

Directions for the use of tables VI, VII and IX. 

Table VI. Pounds of fat in 1 to 10,000 pounds 
of milk testing 3 to 5.35 percent. 

Table VII. Amount due for butter fat, in dol- 
lars and cents, at 12 to 25 cents per pound. 

Table VIII. Relative value tables. 

Table IX. Butter chart, showing calculated 
yield of butter, in pounds, from 1 to 10,000 pounds of 
milk testing 3.0 to 5.3 percent of fat. 

Table X. Overrun table, showing pounds of but- 
ter from 100 pounds of milk. 

Table XI. Yield of cheese, corresponding to 2.5 
to 6 percent of fat, with lactometer readings of 26 to 36. 

Table XII. Comparisons of Fahrenheit and 
Centigrade (Celcius) thermometer scales. 

Table XIII. Comparison of metric and custom- 
ary weights and measures. 

Suggestions regarding the organization of co- 
operative creameries and cheese factories, . - - 205-232 

Index, 233-236 



TESTING MILK AND ITS PRODUCTS. 



INTRODUCTION. 

The need of a rapid, accurate and inexpensive method of 
determining the amount of butter fat in milk and other 
dairy products became more and more apparent, in this 
country and abroad, with the progress of the dairy industry, 
and especially with the growth of the factory system of but- 
ter and cheese making during the last few decades. So 
long as each farmer made his own butter and sold it to pri- 
vate customers or at the village grocery, it was not a matter 
of much importance to others whether the milk produced 
by his cows was rich or poor. But as creameries and cheese 
factories multiplied, and farmers in the dairy sections of 
our country became to a large extent patrons of one or the 
other of these, a system of equitable payment for the milk 
or cream delivered became a vital question. 

1. The need of a practical milk=and cream test. The 
creameries in existence in this country up to within ten 
years were nearly all conducted on the cream-gathering plan: 
the different patrons set their milk, and cream gatherers 
hauled the cream to the creamery, usually twice or three 
times a week, where the mixed lots of cream were then 
ripened and churned. The patrons were paid per inch of 
cream furnished; a creamery inch is a quantity of cream 
which fills a can twelve inches in diameter, one inch 
high, or 113 cubic inches. This quantity of cream is sup- 



2 Testing Milk and Its Products. 

posed to make a pound of butter, but cream from different 
sources, or even from the same sources at different times, 
varies greatly in butter-producing capacity, as will be shown 
under the subject of cream testing (140*). The system of 
paying for the number of creamery inches delivered could 
not therefore long give satisfaction. 

The proposition to take out a small portion, a pint or half 
a pint of the cream furnished by each patron, and deter- 
mine the amount of butter which these samples would make 
on being churned in so-called test churns, found but a very 
limited acceptance, on account of the labor involved and 
the difficulty of producing a first-class article of all the 
small batches of butter thus obtained. 

2. The introduction of the so-called oil test churn (187) 
in creameries, which followed the creamery inch system, 
marked a decided step in advance, and it soon came into 
general use in cream-gathering districts. In this test, glass 
tubes of about f inch internal diameter and nine inches 
long, are filled with cream to a depth of 5 inches, and the 
cream churned; the tubes are then placed in hot water, and 
the column of melted butter formed at the top is read off 
by means of a scale showing the number of pounds of but- 
ter per creamery inch corresponding to different depths of 
melted butter. While the oil test is capable of showing the 
difference between good and poor cream, it can not, accord- 
ing to investigations conducted at the Wisconsin experiment 
station, make strictly accurate distinctions between different 
grades of good and of poor cream. As a result, perfect 
justice can not be done to different patrons of creameries 
where payments for cream delivered are made on the basis 
of this test. 



Refers to paragraph number. 



Introduction. 3 

3. In cheese factories, and since the introduction of the 
centrifugal cream separator, in separator creameries, the 
problem of just payment for the milk furnished by different 
patrons was no less perplexing than in case of gathered- 
cream factories. By the pooling system generally adopted, 
each patron received payment in proportion to the number 
of pounds of milk delivered, irrespective of its quality. 
Patrons delivering rich milk naturally will not be satisfied 
with this system when they find out the quality of their 
milk as compared with that of their neighbors. The temp- 
tation to fraudulently increase the amount of milk delivered, 
by watering, or to lower its quality by skimming, will fur- 
thermore prove too strong for some patrons; the fact that it 
was difficult to prove any fraud committed, from lack of a 
reliable and practical method of milk analysis, rendered 
this pooling system still more objectionable. 

4. As another instance in which the need of a simple 
test for determining the fat content of different kinds of 
milk was strongly felt may be mentioned the case of private 
dairymen and breeders of dairy cattle, who desired to follow 
up the butter-producing capacities of the individual cows in 
their herds. The only manner in which this could be done, 
was by the cumbersome method of trial churnings: by sav- 
ing the milk of the cow to be tested, for a day or a week, 
and churning separately the cream obtained. This re- 
quires a large amount of work when a number of cows are 
to be tested, and can not therefore be done except in com- 
paratively few cases, with cows of great excellence, or by 
farmers having plenty of hired help. 

5. Introduction of milk tests. The first method 
which fulfilled all reasonable demands of a practical and 



4 Testing Milk and Its Products. 

reliable milk and cream test was the Babcock test, invented 
by Dr. S. M. Babcock, chemist to the Wisconsin experiment 
station; a description of the test was first published in 
July, 1890, as bulletin No. 24 of Wisconsin experiment 
station, entitled: A new method for the estimation of fat in 
milk, esi^ecially adapted to creameries and cheese factories. 
This test which is now known and adopted in all parts of 
the world where dairying is an important industry, was 
not, however, the first method proposed for this purpose 
which could be successfully operated outside of chemical 
laboratories, It was preceded by a number of diflferent 
methods, the first one published in this country being 
Short's method, invented by Mr. F. G. Short, and described 
in bulletin No. 16 of Wisconsin experiment station in July, 
1888. 

6. Short's test. In this ingenious method, a certain 
quantity of milk (20 cc.*) was boiled with an alkali solution, 
and afterwards with a mixture of sulfuric and acetic acids; a 
layer of insoluble fatty acids separated on top of the liquid, 
and was brought into the graduated neck of the test bottles 
b}^ addition of hot water; the reading gave the per cent, of 
fat in the sample of milk tested. 

Short's method did not find very wide application, both 
because it was rather lengthy and its manipulations some- 
what difficult for non-chemists, and because several other 
methods were published shortly after it had been given to 
the public. 

7. Other milk tests. Of these may be mentioned, 
besides the Babcock test, already spoken of, the Failyer 
and Willard method,! Parson's method,t Cochran's test,§ 

* See 44, footnote. f Kansas experiment station report, 1888, p. 149. 

% N. H. experiment station report, 1888, p. 69. 
? Journal of Anal. Chem., Ill (1889), p. 3S1. 



Introduction. 5 

the Patrick or Iowa station test,^ and the Beimling (Lefif- 
mann and Beam) test.t Of foreign methods published at 
about the same time, or previously, the lactocrite,+ Lieber- 
mann's method, || the Schmid,^ Thoerner,*[ and Roese- 
Gottlieb** methods may be noted. 

8. AH these tests were similar in principle, the solids 
not fat of the milk being in all cases dissolved by the action 
of one or more chemicals, and the fat either measured as 
such in a narrow graduated tube, or brought into solution 
with ether, gasoline, etc., and a portion thereof weighed on 
evaporation of the solvent. While this principle is an old 
one, having been employed in chemical laboratories for 
man}' years past, the adaptation of it to practical conditions, 
and the details as to apparatus, and chemicals used were of 
course new and different in each case. The American tests 
given were adopted to a limited extent within the states in 
which they originated, and even outside of them, as in case 
of the Short, Patrick and Beimling methods. The Babcock 
test soon, however, nearly everywhere replaced the different 
methods mentioned, and during the past five or six years it 
has been in practically exclusive use in creameries and 
cheese factories in this country where payments are made 
on basis of the qualit}" of the milk delivered, as well as in 



* la. exp. sta., bull. No. 8, February, 1890; Iowa Homestead, June 14, 1889. 

t Vermont exp. sta., bull. No. 21, September, 1890. For description of these 
and other volumetric methods of milk analysis, see Wiley, Agricultural Analysis, 
Vol. Ill, p. 490, et seq ; Wing, Milk and its Products, p. 33, et seq; and Snyder, 
Chemistry of Dairying, pp. 112-113. 

X Analyst, 1887, p. 6. 

II Fresenius' Zeitschr. 22, 383. 

gibid. 27, 464. 

\ Chem. Centralbl., 1892, 429. 

** Landw. Vers. Stat., 40. 1. 



6 Testing Milk and Its Products. 

the routine work in experiment station laboratories, and 
among milk inspectors and private dairymen. , 

9. The Babcock test. An examination of the causes 
of the present general adoption of the Babcock test will 
show the strong points of the test, and the requirements 
made of a practical milk test. The main causes why this 
test has replaced all competitors are doubtless to be sought 
in its simplicity and its cheapness: Its manipulations are 
few and easily learned, and it is cheap, both in first cost and 
as regards running expenses. 

The test is speedj^, and accurate within one or two-tenths 
of one per cent.* 

Only one chemical is used, and no training in or knowl- 
edge of chemistry is required on part of the operator. 

The percentages of fat in the samples tested are shown 
directly from the readings of the fat column, without refer- 
ence to a scale or table. 

Only a small quantity of milk is used (about two-thirds 
of an ounce, 17.6 cc.) 

The apparatus is easily kept in order, and the chances of 
accidents in operating the test, with properl}^ made machines, 
are very slight indeed. 

A small and a large number of samples may furthermore 
be tested with equal facility at the same time, up to the 
capacity of the tester. 

The results obtained may be easily verified b}' renewed 
tests in the same or another machine. 

The test bottles when charged with the samples of milk 



* For a summary of comparative analyses made by the Babcock test and 
gravimetric analysis up to 1892, see Hoard's Dairyman, Oct. 7, 1892, p. 2560; also 
Schrott, Milchzeitung, 1896, p. 183, et seq. 



Int7'oduction. ' 7 

or other dair}' products may be left for months, if desired, 
before the test is completed, and correct results still be 
obtained. 

The completed tests will keep indefinite!}- in the bottles, 
so that the results may be verified at any future time, if 
desired. 

Sour milk may be analyzed with perfect • assurance of 
accurate results, provided it can be properly sampled. 

The test is finally applicable, besides to full milk, to cream, 
skim milk, butter milk, whey, condensed milk and (if a small 
scale for weighing out the sample is available) to cheese. 

10. With all these advantages, the Babcock milk test is 
not in every respect an ideal test. The handling of the 
very corrosive sulfuric acid requires constant care and 
attention; the speed of the tester, the strength of the acid, 
the temperature of the milk to be tested, and other points, 
always require watching, lest the results obtained be too 
low, or otherwise unsatisfactory. The test is, however, for 
general purposes, in the opinion of the writers, the very 
best at our disposal, and in the hands of careful intelligent 
operators, will easil}- give most satisfactory results. 

11. Foreign methods. In European countries three 
practical milk and cream tests, besides the Babcock test, 
are in use at the present time, viz : Gerhers acid-hutyrome- 
ter, De LavaVs huiyrometer. and Fjord's cejitrifugal cream test.^ 

Of these, the last test given has never been introduced 
into this country, to our knowledge, and the former two, 
only on a small scale. 



* The Lister-Babcock milk test advertised in English papers and known as 
such in England, is the regular Babcock test, to which the English manufacturers 
have prefixed their name. 



8 



Testing Milk and Its Products. 



12. The Qerber method* (fig. 1) is essentially the 
old Beimling method worked out independently by the Swiss 

chemist, Dr. N. Grerber. 
In this test sulfuric acid 
of the same strength is 
used as in the Babcock 
test, and a small quantity 
of amyl alcohol is added. 
The amyl alcohol facili- 
tates the separation of 
the fat, but introduces 
a source of error which 
may become serious, and 
especially so, where the 
results obtained with a 

Fig. 1. The Gerber acld-butyrometer. ^gw lot of amyl alcohol 

can not be compared with gravimetric analysis or with 
tests made with amyl alcohol known to give correct results. 

13. In the De Laval butyrometer (fig. 2) the same 
acid is used as in the Babcock test, but the tubes employed, 
and the manipulations of the method differ materially from 
this test; a smaller sample of milk is taken (only 2 cc.) 
and a correspondingly small quantity of acid used. The 
results obtained are correct. Where a large number of milk 
samples are tested every day, as is the case, for instance, in 
European milk control stations, the butyrometer may be 
preferable to the Babcock test; but it requires more skill of 
the operator and is more difficult to work satisfactorily in 
case of milk which cannot be easily sampled, as sour, lop- 
pered, or partially churned milk. The machines placed on 




* Gerber, Die Praktische Milch-Pruefung. 



Introduction. " 9 

the market both by Dr. Gerber and the De Laval Company 
are more expensive than the Babcock testers sold in this 
country; the De Laval test requires a high speed, 5-6000 





Fig. 2. De Laval's butyrometer. 

revolutions per minute, and therefore places greater de- 
mands for solidity in the machine than does the Babcock test. 
14. Fjord's centrifugal cream tester* (fig. 3) is ex- 
tensively used in Denmark and is mentioned in this connec- 
tion as it furnishes a fairly 
reliable method for compar- 
ing the quality of different 
lots of milk. The method 
was published in 1878, b}^ 
the late N. J. Fjord, director 
of the state experiment sta- 
tion in Copenhagen, through 

Fig. 3. Fjord's centrifugal cream tester. whoSC excrtioUS and On 







* State Danish experiment station, Copenhagen, sixth and ninth reports, 

1885-7. 



lo • Testing Milk and Its Pj'oducts. 

whose authority it was generally introduced into Danish 
creameries in the middle of the eighties. No chemicals are 
added in this test, the milk being simply placed in glass 
tubes, seven inches long and about 2-3 of an inch in diame- 
ter, and whirled for twenty minutes at a rate of 2000 revo- 
lutions per minute at 55° C. (131° F.) The reading of the 
cream layer thus obtained gives the per cent, of cream, and 
not of butter fat, in the sample tested. 192 samples of milk 
can be tested simultaneously. Within the limits of normal 
Danish herd milk, the results obtained correspond to the 
percents of fat present in the samples, one per cent, of 
cream being equal to about 0.7 per cent, of fat; outside of 
these limits the test is, however, unreliable, especially in 
case of very rich milk and strippers' milk. Only sweet milk 
can be tested by this method. The recent introduction of 
milk tests proper into Denmark, like the Grerber, Babcock 
and De Laval tests, will, however, in all probability in time 
force the Fjord cream test out of Danish creameries, for 
similar reasons that relegated to obscurity the gravity cream 
tests (creamometers.) 

Before going over to the main part of the present work, 
the discussion of the Babcock milk test, a brief description 
of the chemistry of milk and its products is given, so that the 
student may understand what are the components of dairy 
products, and the relation of these to each other. Only 
such points as have a direct bearing on the subject of milk 
testing and the use of milk tests in butter and cheese fac- 
tories or private dairies will be treated in this chapter, and 
the reader is referred to standard works on dairying for 
further information in regard to the composition of dairy 
products. 



Composition of Milk and Its Products. 1 1 



CHAPTER I. 
COMPOSITION OF MILK AND ITS PRODUCTS. 

15. Milk is composed of the following substances: 
water, fat, casein, albumen, milk sugar and ash. A few other 
substances are present in small quantities, but are of no 
practical importance and will not be considered here. The 
components of the milk less the water are known, collect- 
ively, as milk solids, or total solids, and the total solids less 
the fat, i. e. casein, albumen, milk sugar, and ash, are often 
spoken of as solids not fat, or the non-fatty milk solids. The 
milk serum includes all components of the milk less the fat; 
the serum solids are therefore another name for the solids 
not fat; when given, they are, however, generally calculated 
to per cent, of milk serum, not of milk. If, e. g., a sample 
of milk contains 9 per cent, of solids not fat, and 3 per cent, 
of fat, the milk serum will make up 97 per cent, of the 
milk, and the serum solids, .^j = 9.28 per cent, of the milk 
serum. 

IG. Water. The amount of water contained in milk 
ranges from 80 to 90 per cent. Normal cows' milk will not 
as a rule contain more than 88 per cent, of water, nor less 
than 84 per cent. In states where there are laws regulating 
the sale of milk, as is the case m eighteen states in the 
Union (see Appendix), the maximum limit for water in milk 
in all instances but one (South Carolina) is 88 per cent. ; the 
state mentioned allows 88.5 per cent, of water in milk offered 



12 Testing Milk and Its Products. 

for sale within her borders. The effect of fraudulently in- 
creasing the water content of milk by watering is considered 
under Adulteration of Milk. 

17. Fat. The fat in milk is not in solution, but sus- 
pended as very minute globules, which form an emulsion 
with the milk serum; the globules are present in immense 
numbers, viz: on the average about one hundred million in 
a single drop of milk; a quart of milk will contain about 
two thousand billions of fat globules, a number written with 
thirteen ciphers. The size of the globules in the milk from 
the same cows varies according to the stage of the period 
of lactation, the globules being largest at the beginning of 
the lactation period, and gradually decreasing in size with 
its progress. Different breeds of cows have fat globules of 
different average sizes; the Channel Island cows are thus 
noted for the relatively large fat globules of their milk, 
while the Lowland breeds, the Ayrshire, and other breeds 
have uniformly smaller globules. The diameter of average 
sized fat globules in fresh milkers is about 0.004 millimeter, 
or one-six thousandth of an inch; that is, it takes about six 
thousand such globules placed side by side to cover one 
inch in length. The globules in any sample of milk vary 
greatly in size; the largest globules are recovered in the 
cream when the milk is set, or run through a cream sepa- 
rator, and the smallest ones remain in the skim milk; prop- 
erly skimmed separator skim milk will contain only a small 
number of very minute fat globules. 

Milk fat is composed of so-called glycerides of the fatty 
acids, i. e. compounds of the latter with gl3'cerine; some of 
the fatty acids are insoluble in water, viz: palmitic, stearic, 
and oleic acids, while others are soluble and volatile, the 



Comj>osition of Milk and Its Products. 13 

chief ones among the latter being butyric, caprylic, and 
caproic acids. The glycerides of the insoluble fatty acids 
make up about 92 per cent, of the pure milk fat, and about 
8 per cent, of the glycerides of volatile fatty acids are there- 
fore found in natural milk- (and butter-) fat. The distinc- 
tion between natural and artificial butter lies mainly in this 
point, since artificial butter (butterine, oleomargarine) as 
well as other solid animal fats contain only a very small 
quantity of volatile fatty acids. The glycerides of the vola- 
tile fatt}^ acids are unstable compounds, easily decomposed 
through the action of bacteria or light; the volatile fatty 
acids thus set free, mainly butyric acid, are the cause of 
the unpleasant odor met with in rancid butter. 

The per cent, of fat in cows' milk is generally between 
three and six per cent. American milk contains on the 
average toward four per cent, of fat. The milk from single 
cows in perfect health will occasionally go below or above 
the limits given, but the mixed milk from a whole herd 
rarely falls outside of these limits. The legal standard for 
fat in milk in most states of the Union is 3 per cent.; Rhode 
Island allows milk containing 2.5 per cent, of fat to be sold 
as pure, while Georgia and Minnesota require it to contain 
3.5 per cent, and Massachusetts 3.7 per cent, (in the months 
of May and June; see Appendix.) 

18. Casein and albumen. These belong to the so- 
called nitrogenous substances, distinguished from the other 
components of the milk by the fact that they contain the 
element nitrogen. Another name is albuminoids or 
protein compounds. Casein is precipitated by rennet in the 
presence of soluble calcium salts, and by dilute acids and 
certain chemicals; albumen is not acted upon by these 



14 Testing Milk and Its Products. 

agents, but is coagulated b3^ heat, a temperature of 170° F. 
being sufficient to effect a perfect coagulation. The casein, 
with fat and water, form the main components of most 
kinds of cheese; in the manufacture of cheddar and most 
other solid cheeses, casein is coagulated by rennet, and the 
curd thus formed holds fat and whey mechanically, the 
latter containing in solution small quantities of non-fatty 
milk solids. The albumen goes into the whey, and in some 
countries is also made into cheese by evaporating the whey 
under constant stirring; usually whole milk of cows or goats 
is added and incorporated into such cheese {primost^ goat 
cheese). 

Casein is present in milk partly in solution, in the same 
way as milk sugar, soluble ash-materials and albumen, and 
partly in suspension, in an extremel}^ fine colloidal condi- 
tion, mixed or combined with insoluble calcium phosphates. 
The casein and calcium phosphates in suspension in milk 
may be retained on a filter made of porous clay (so-called 
Chamherland filters). 

About 80 per cent, of the nitrogenous compounds of nor- 
mal cows' milk are made up of casein; the rest is largely 
albumen. If the amount of casein in milk be determined 
by precipitation with rennet or dilute acids, and the albu- 
men by boiling the filtrate from the casein precipitate, it 
will be found that the sum of these two compounds does 
not make up the total quantity of nitrogenous constituents 
in the milk. The small remaining portion (about five per 
cent, of the total nitrogenous constituents) is called by vari- 
ous authors, globulin, albumose, hemi-albumose, nuclein, 
proteose, etc. The nitrogenous constituents of milk are 
very unstable compounds, and their study presents many 
and great difficulties; as a result we find that no two scien- 



Composition of Milk and Its Products. 15 

tists who have made a special study of these compounds 
agree as to their properties, aside from those of casein and 
albumen, or their relation to the nitrogenous substances 
found elsewhere in the animal body. For our purpose we 
may, however, consider the nitrogen compounds of milk as 
made up of casein and albumen, and the term casein and 
albumen used in this book is meant to include the total 
nitrogenous constituents of milk, as obtained by multiplying 
the total nitrogen content of the milk by 6.25.* 

The quantity of casein in normal cows' milk will vary 
from 2 to 3.5 per cent., and of albumen from .5 to .8 per cent. 
The total content of casein and albumen will range between 
2.5 and 4.2 per cent, the average being about 3.5 per cent. 
Milk with a low fat content will contain more casein and 
albumen, than fat, while the reverse is generally true in case 
of milk containing more than 3.5 per cent, of fat. 

19. Milk sugar or lactose belongs to the group of or- 
ganic compounds known as carbohydrates. It is a commer- 
cial product manufactured from whe}^, and is obtained in 
this process as pale white crystals, of less sweet taste, and less 
soluble in water than ordinary- sugar (cane sugar, sucrose). 
About 70 per cent, of the solids in the whey, and 33 per 
cent, of the milk solids, are composed of milk sugar. 

When milk is left standing for some time, viz: from one to 
several days, according to the temperature of the surround- 
ing medium, it will turn sour, and soon become thick and 
loppered. This change in the composition and the appear- 
ance of the milk is brought about througrh the action of 



* The factor 6.2.5 is generally used for obtaining the casein and albumen from 
the total nitrogen in the millc, although 6.37 would be more correct, since these 
substances, .according to our best authorities, contain on the average 15.7 per cent, 
of nitrogen. 



1 6 Testing Milk and Its Products, 



d 



acid-forming bacteria on the milk sugar; these are present 
in ordinary milk in immense numbers, and under favorable 
conditions of temperature multiply rapidly, feeding on the 
milk sugar as they grow, and decomposing it into lactic 
acid. When this change alone occurs, there is not neces- 
sarily a loss in the nutritive value of the milk, since the milk 
sugar breaks up directly into lactic acid; this is shown 
by the following chemical formula: 

Ci„H,„0„. HoO {lactose) =-4: Q,Yi,Oz (lactic acid.)'' 

Ordinarily the souring of milk is, however, more com- 
plicated, and other organic bodies, like butyric acid, 
alcohol, etc., and gases like carbonic acid and hydrogen 
are formed, resulting in a loss in the feeding value of the 
milk. While sour milk may therefore contain a somewhat 
smaller proportion of food elements than sweet milk, the 
feeding of it to farm animals, especially pigs, will generally 
produce better results than is obtained in feeding similar 
milk in a sweet condition. The cause of this may lie in the 
stimulating effect of the lactic acid of the sour milk on the 
appetites of the animals, or in its aiding digestion by in- 
creasing the acidity of the stomach juices. 

That the souring of milk is due to the activities of bac- 
teria present therein is shown clearly by the fact that steril 
milk, i. e., milk in which all germ life has been killed, will 
remain sweet for any length of time when kept free from 
infection. 

The amount of milk sugar found in normal cows' milk 
varies from 3 to 6 per cent, the average content being about 



* One molecule of milk sugar is composed of 12 atoms of carbon (C), 22 atoms 
of hydrogen (H), 11 atoms of oxygen (0), and one molecule of water (HjO). In 
the same way, the lactic acid molecule consists of :> atoms of carbon, 6 atoms of 
hydrogen, and 3 atoms of oxygen. 



Co7npositwn of Milk and Its Products. 17 

5 per cent.; in sour milk this content will be decreased to 
toward 4 per cent. 

20. Ash. The ash or mineral substances of milk are 
largely composed of chlorids and phosphates of sodium, 
potassium, magnesium and calcium; iron oxid, and sulfuric 
and citric acids are also present in small quantities among 
the normal mineral milk constituents. The amounts of the 
different bases and acids found in milk ash have been deter- 
mined by a number of chemists; the average figures ob- 
tained are given in the following table, calculated per 100 
parts of milk (containing .75 per cent, of ash) and per 100 
parts of milk ash. 

Mineral Components of Milk. 

In per cent, of Milk. In per cent, of Ash. 

Potassium oxid (K^O) 19 per ct. 25.64 per ct. 

Sodium oxid (NajO) 09 12.45 

Lime(CaO) 18 24.58 

Magnesia (MgO) 02 3.09 

Iron oxid (FcjOg) 002 .34 

Phosphoric anhydrid (P2O5) 16 21.24 

Chlorin (CI) 12 16.34 

.762 per ct. 103.68 per ct. 
Less oxygen, corresponding to 

chlorin 012 3.68 

.75perct. 100.00 per ct. 

The combinations in which the preceding bases and acids 
are contained in the milk are not known with certainty; the 
following scheme is, however, given on the best authority 
and is believed to be substantially correct. 
2 



1 8 Testing Milk and Its Products. 

Percentage Composition of Milk Ash {Soeldner). 

Sodium chlorid (common salt) 10.62 per ct. 

Potassium chlorid — 9 16 

Mono-potassium phosphate 12.77 

Di-potassium phosphate 9.22 

Potassium citrate 5.47 

Di-magnesium phosphate 3.71 

Magnesium citrate 4.05 

Di-calcium phosphate 7.42 

Tri-calcium phosphate 8.90 

Calcium citrate 23.55 

Lime combined with casein 5.13 

100.00 

According to the same author, 36 to 56 per cent, of the 
phosphoric acid found in milk, and from 53 to 72 per cent, 
of the lime, are present in suspension in the milk, as di- and 
tri-calcium phosphates, and may be filtered out by means 
of Chamberland filters (18), or by long continued centrifuging 
(Babcock *.) The rest of the ash constituents are dissolved 
in the milk serum. 

The ash content of normal cows' milk varies but little, as 
a rule only between .6 and .8 per cent, with an average of 
.7 per cent. Milk with a high fat content generally con- 
tains about .8 per cent, of ash; strippers' milk always has a 
high ash content, at times even exceeding one per cent. 
Ordinarily, the mineral constituents of milk are, however, 
the components least liable to variations. 

21. Other components. Besides the milk constituents 
enumerated and described in the preceding pages, normal 
milk contains a number of substances which are only pres- 
ent in small quantities and have only scientific interest, such 



* Wisconsin experiment station, twelfth report, p. 93. 



Comfositioyi of Milk and Its Products, 19 

as the milk gases (carboaic acid, oxygen, nitrogen), citric 
acid, lecithin, cholesterin, urea, h3^poxanthin, lactochrome, 
etc. 

The percentage composition of cows' milk will be seen 
from the tables given in the Appendix. Tables are also given 
showing the average composition of milk products, like skim 
milk, butter milk, whey, cream, butter, cheese and condensed 
milk. 

22. Colostrum milk. The liquid secreted directly after 
parturition is known as colostrum milk or biestings. It is a 
thick, yellowish, viscous liquid; its high content of albumen 
and ash is characteristic, and also its low content of milk 
sugar. Owing to the large quantit}' of albumen which 
colostrum contains it will coagulate on being heated to 
boiling. The secretion of the udder gradually changes from 
colostrum to normal milk in the course of four to five days; 
the milk is considered fit for direct consumption, or for the 
manufacture of cheese and butter when it does not coagu- 
lated on boiling, and is of normal appearance as regards 
color, taste, and other properties. For composition of colos- 
trum milk, see Appendix. 



20 Testing Milk and lis Products. 



CHAPTER II 
SAMPLING MILK. 

23. The butter fat in milk is not in solution, like sugar 
dissolved in water, but the minute fat globules or drops, in 
which form it occurs, are held in suspension in the milk 
serum (17). Being lighter than the serum, the fat globules 
have a tendency to rise to the surface of the milk. If, there- 
fore, a sample of milk is left undisturbed for even a short 
time, the upper layer will contain more fat than the lower 
portion. This fact should always be borne in mind when 
milk is sampled. The rapidity with which fat rises in milk 
can be easily demonstrated by leaving a quantity of sweet 
milk undisturbed in a cylinder or milk can for a few minutes, 
and testing separately the top, middle and bottom layer of 
this milk. 

Experiment. Fill the cylinder used for making the lactometer 
test (100) with milk, thoroughly mixed by pouring; measure a pip- 
etteful of milk immediately into test bottle A. Allow the milk in 
the cylinder to remain undisturbed for ten minutes, and then 
measure a pipetteful of milk from the top of that in the cylinder, 
into test bottle B. Next pour out most of the milk from the 
cylinder, and measure into test bottle C, a pipetteful of the last 
portion of the milk in the cylinder. 

After completing the tests of A, B, and C, in the usual manner 
(32), record the results of each test in the note book. 

24 . The amount of mixing necessary to evenly distribute 
the constituents of milk throughout its mass, can also be 



Sampling Milk. 21 

demonstrated by adding a few drops of cheese color to a 
quart of milk. The yellow streaks through the milk will be 
noticed until it has been poured several times from one vessel 
to another, when the milk will have a uniform pale yellow 
color. Stirring with a stick or a dipper will not produce an 
even mixture so quickly or so completely as pouring the milk 
a few times from one vessel to another, and in sampling milk 
for testing it should always be mixed by pouring just before 
the milk is measured into the bottle; if several tests are 
made of a sample, the milk should be poured before each 
sampling. 

25. Partially churned milk. A second difficulty some- 
times met with in sampling whole milk arises from the fact 
that a part of the butter fat may be separated in the form of 
small batter granules by too zealous mixing, or by reckless 
shaking in preparing the sample for testing. This will 
happen most readily in case of milk from fresh cows, or with 
milk containing exceptionally large fat globules. When 
some of the butter granules are thus churned out, they very 
quickly rise to the surface of the milk after pouring, and 
cannot again be incorporated in the milk by simple mixing; 
it is, therefore, impossible to obtain a fair sample of such 
milk for testing, without taking special measures which will 
be explained in the following. The granules of butter may 
be so small as to pass into the pipette with the milk, and the 
quantity measured thus contain a fair proportion of them, 
but they will be found sticking to the inside of the pipette 
when this is emptied, and so fail to be carried into the test 
bottle with the milk. 

A similar partial churning of the milk will sometimes take 
place in the transportation cans. When such milk is received 



22 Testing Milk and Its Products, 

at the factory, the butter granules are caught by the strainer 
cloth through which the milk is poured, and thus lost both 
to the factory and to the farmer. This separated fat cannot 
be put into the cream, or added to the granular butter, with- 
out running the risk of making mottled butter, and it will 
not enter into the sample of milk taken for testing purposes. 

When milk samples are sent in small bottles by mail or 
express, or carried to the place of testing, they very often 
arrive with lumps of butter floating in the milk or sticking 
to the glass. This churning of the milk can be easily pre- 
vented by filling the bottle or the can completely with milk. 
If there is no space left for the milk in which to splash 
around, the fat will not be churned out in transit. 

26. Approximately accurate results may generally be 
obtained with a partially churned sample of milk, if a tea- 
spoonful of ether is added to it. After adding the ether, 
cork the bottle and shake it until the lumps of butter are 
dissolved in the ether. This ether solution of the butter 
will mix with the milk, and from the mixture a uniform 
sample may generally be taken without difficult}^ The 
dilution of milk by the ether introduces an error in the test- 
ing, and only the smallest quantity of ether necessar}^ to 
dissolve the lumps of butter should be used. If desired, a 
definite quantity of ether, say 5 or 10 per cent, of the volume 
of the sample of milk to be tested, may be added; in such 
cases the result of the test must be increased b}' the per cent, 
of ether added. 

Example. To a 4 oz. sample (120 cc.) of partially churned 
milk, 5 per cent., or 6 cc, of common ether are added: the mixture 
gives an average test of 4.2 per cent. The test must be increased 
by f§gX4.2=.21, and the original milk, therefore contained 4.2 
+ .21=4.41 per cent, of fat. 



Sam fling Milk. 23 

Instead of adding ether to partiall}' churned samples, it 
has been suggested to warm the milk to 110° F. for a suffi- 
ciently long time to melt the butter granules; the sample is 
now shaken vigorously until a uniform mixture of milk and 
melted butter is obtained, and a pipetteful then drawn from 
the sample. 

27. Sampling sour milk. When milk becomes sour, the 
casein is coagulated and the mechanical condition of the milk 
thereby changed so as to render a proper sampling very diffi- 
cult. The butter fat is not, however, changed in the process 
of souring: this has been shown by one of us in a series of 
tests which were measured from one sample of sweet milk 
into six test bottles. A test of the milk in one of these 
test bottles was made every month for six months, and ap- 
proximately the same amount of fat was obtained in the 
tests throughout the series, as was found originally in the 
milk when tested in a sweet condition.* If the milk is in 
condition to be sampled, the souring of it does not therefore 
interfere with its being tested b}^ the Babcock test, or with 
the accuracy of the results obtained. 

In order to facilitate the sampling of sour or loppered 
milk, some chemical is added which will re-dissolve the 
coagulated casein and produce a uniform mixture, that can 
be readil}' measured with a pipette. An}- alkali (powdered 
potash or soda, or liquid ammonia) will produce this effect. 
Only a very small quantit}^ of powdered alkali is necessary 
for this purpose. The complete action of the alkali on sour 
milk requires a little time, and the operator should not try 
to hasten the solution by adding too much alkali. An ex- 



*See Hoard's Dairyman, April 8, 1892. The same holds true for cream, as 
shown by Winton, (U. S. Dept. Agr., Div. of Chemistry, bull. 43, p. 112.) 



24 Testing Milk and Its Products, 

cess of alkali will often cause such a violent action of the 
sulfuric acid on the milk to which the acid is added, (on ac- 
count of the heat generated or the presence of carbonates in 
the alkali) that the mixture will spurt out of the neck of 
the test bottle, when it is shaken in mixing the milk and 
the acid. When powdered alkali is added to the milk, it 
should be allowed to stand for a while, with frequent stirring, 
until the curd is all dissolved, and an even translucent liquid 
is obtained. Such milk may become dark colored by the 
action of the alkali, but this color does not interfere with 
the accuracy of the test. 

Instead of powdered soda or potash, these substances dis- 
solved in water (soda or potash lye), or strong ammonia 
water, may be used for the purpose of dissolving the coagu- 
lated casein in a sample of sour milk. In this case, a defi- 
nite proportion of alkali solution must, however, be taken, 
5 per cent, of the volume of milk being usually sufficient, 
and the results obtained are increased accordingly. (See 
example cited on p. 22). 

28. Sampling frozen milk. When milk freezes, it 
separates into two distinct portions: Milk crystals, largely 
made up of water, with a small admixture of fat and other 
solids, and a liquid portion, containing nearly all the 
solids of the milk. In sampling frozen milk it is there- 
fore essential that hotli the liquid and the frozen part be 
warmed and mixed thoroughly on the disappearance of the 
crystals, by pouring gently back and forth from one vessel 
into another; the sample is then taken and the test proceeded 
with in the ordinary manner (32). 



The Babcock Test. 



25 



CHAPTER III. 

THE BABCOCK TEST. 

29. The Babcock test is founded on the fact that strong 
sulfuric acid will dissolve all non-fattj^ solid constituents of 

milk and other dairy 
products, and will set 
free the fat. This will 
separate on standing, 
but to effect a speedy 
and complete separa- 
tion, the bottles holding 
the mixture of milk 
and acid are placed in 
a centrifugal machine 
— a so-called tester^ and 
whirled for five min- 
utes; hot water is then 
added so as to bring 
the liquid fat into the 
graduated neck of the 
test bottles, and after 
a repeated whirling, 
the length of the col- 
umn of fat is read off, 

Fig. 4. The first Babcock tester made. showino" the per CCnt. 

of fat contained in the sample tested. 




26 Testing Milk and Its Products. 

Sulfuric acid is preferable to other strong mineral acids 
for the purpose mentioned, on account of its affinity for 
water; when mixed with milk, the mixture heats greatly, 
thus keeping the fat liquid without the application of arti- 
ficial heat, and rendering possible a distinct reading of the 
column of fat brought into the neck of the test bottles. 

30. So far as is known, any kind of milk can be tested 
by the Babcock test. Breed, period of lactation, quality 
or age of the milk is of no importance in using this method, 
so long as a fair sample of the milk can be secured. Sam- 
ples of milk or other dairy products, rich in solids, require 
a little more effort to perfect a thorough mixture with the 
acid than thin milk or other dairy products low in solids, 
like whey, which may be readily mixed with the acid. 

A — Directions for Making the Test. 

31. The various steps in the manipulation of the Bab- 
cock test are discussed in the following pages; attention is 
drawn to the difficulties which the beginner and others may 
meet with in working the test, and the necessary precautions 
to be observed in order to obtain accurate and satisfactory 
results are explained in detail. The effort has been to treat 
the subject exhaustively, and from a practical point of view, 
so that persons as j^et unfamiliar with the test may turn to 
the pages of this book for help in any difficulties which they 
ma}' encounter in their work in this line. 

32. Sampling. The sample to be tested is first mixed 
by pouring the milk from one vessel to another two or three 
times so that every portion thereof will contain a uniform 
amount of butter fat. The measuring pipette which has a 
capacity of 17.6 cubic centimeters, (see fig. 6), is filled with 
the milk immediately after the mixing is completed, by 



The Babcock Test. 



27 



dl 



sucking the milk into it until this rises a little 
above the mark around the stem of the pipette; 
the forefinger is then quickly placed over the end 
of the pipette before the milk runs down below 
the mark. By loosening a little the pressure of the 
finger on the end of the pipette, the milk is now al- 
lowed to run down until it just 
reaches the mark on the stem; 
the quantity of milk contained in 
the pipette will then, if this is cor- 
rectl}' made, be exactly 17.6 cc. 
The finger should be dry in meas- 
uring out the milk so that the de- 
livery of milk ma}^ be checked b}' 
gentle pressure on the upper end 
of the pipette. 

The point of the pipette is now 
placed in the neck of a Babcock 
test bottle (fig. 5) and the milk is 
allowed to flow slowly down the '^^^iS 
inside of the neck. Care must be 
taken that none of the milk meas- 
ured out is lost in this transfer. 
The portion of the milk remain 
in the point of the pipette is blown 
into the test bottle. 

The best and safest manner of 
holding the bottle and the pipette 
in this transfer is shown in fig. 7. 
Fig. 8 shows a position which 
should be avoided, since by holding 

Fig 5. Babcock Fig. 6 



milk test bottle. 



17.6 cc. pipette. 



28 



Testing Milk and Its Products. 



the bottle in this way, there is a danger that some of the 
milk may completely fill the neck of the bottle, and as a 
result, flow over the top of the neck. 




Fig. 7. The right way of emptying pipette into test bottle. 

33. Adding acid. The acid cylinder, (fig. 9), holding 
17.5 cc, is then filled to the mark with sulfuric acid of a 
specific gravity of 1,82-1.83. This amount of acid is care- 
fully poured into the test bottle containing the milk. In 
adding the acid, the test bottle is conveniently held at an 



The Babcock Test. 



29 



angle, (see fig. 7), so that the acid will follow the wall of the 
bottle and not run in a small stream into the center of the 
milk. By pouring 
the acid into the 
middle of the neck 
of the test bottle,, 
there is also a dan- 
ger of completel}^ 
filling this with acid, 
in which case the 
plug of acid formed 
will be pushed over 
the edge of the neck 
by the expansion of 
the air in the bottle, 
and may be spilled 
on the hands of the 
operator. 

The milk and the 
acid in the test bot- 
tle should be in two 
distinct layers, with- 
out anj^ black por- 
tion of partially 
mixed liquids be- 
tween them. Such pj^ g ^he wrong way of emptying pipette into 

a dark layer is often t^^t bottle. 

followed by an indistinct separation of the fat in the final 
reading. The cause of this is possibly that a partial mix- 
ture of acid and milk before the acid is diluted with the 
water of the milk may bring about too strong an action of 
the acid on the milk, and the fat in this small portion may 




30 



Testing Milk and lis Products. 




be slightly charred by the strong acid. The appearance of 
black flocculent matter in or below the column of fat which 
generally results, in either case renders a cor- 
rect measurement of fat difficult, and at 
times even impossible; if the black specks 
occur in the fat column itself, the readings are 
apt to be too high; if below it, the difficulty 
comes in deciding where the column of fat 
begins. 

34. Mixing milk and acid. After ad- 
ding the acid, this is carefully mixed with the 
milk b}^ giving the test bottle a rotary motion. 
In doinoj this, care should be taken that none 

Fig. 9. 17 5 cc. => ' 

acid cylinder. of the liquid spurts into the neck of the test 
bottle. When once begun, the mixing should be continued 
until completed; a partial and interrupted mixing of 
the liquids will often cause more or less black 
material to separate with the fat when the test is 
finished. Clots of curd which separate at first by the action 
of the acid on the milk, must be entirely dissolved by per- 
sistent and careful shaking of the bottle. Beginners some- 
times fail to mix thoroughly the milk and the acid in the 
test bottle. As the acid is much heavier than the milk, a 
thin layer of it is apt to be left unnoticed at the bottom of 
the bottle, unless this is vigorously shaken toward the end 
of the operation. 

The mixture becomes hot by the action of the acid on the 
water in the milk and turns dark colored, owing to the effect 
of the strong sulfuric acid on the nitrogenous constituents 
and the sugar of the milk. 

Colostrum milk, or milk from fresh cows will form a 
violet colored mixture with the acid, owing to the action of 



The Babcock Test. 31 

the latter on the albumen present in considerable quantities 
in such milk (22). 

When milk samples are preserved by means of potassium 
bichromate (172), and so much of this material has been added 
that the milk has a dark yellow or reddish color, the mix- 
ture of milk and acid will turn greenish black, and a com- 
plete solution is rendered extremely diflScult on account of 
the toughening effect of the bichromate on the precipitated 
casein. An indistinct separation of the fat is also some- 
times obtained in such samples, but this difficulty can gen- 
erally be overcome by using a little less than the regular 
quantity of acid. 

35. Whirling bottles. After the milk and the acid 
have been completely mixed, the test bottle is at once placed 
in the centrifugal machine or tester and whirled for four to 
five minutes at a speed of 600 to 1,200 revolutions per min- 
ute, the proper speed being determined by the diameter of the 
tester (57). It is not absolutely necessary to whirl the test 
bottles in the centrifuge as soon as the milk and the acid are 
mixed; they may be left in this condition for any reasonable 
length of time (24 hours, if necessary) without the test be- 
ing spoiled. If left until the mixture becomes cold, the 
bottles should, however, be placed in warm water (of about 
160° F.) for about 15 minutes before whirling. 

Four minutes at full speed is usually sufficient for the 
first whirling of the test bottles in the centrifuge; this will 
bring the fat to the surface of the liquid in the body of the 
bottle. 

36. Adding water. Hot water is now added by 
means of a pipette, or some special device, until the bottles 
are filled up to the beginning of the neck. The bottles are 



32 Testing Milk and Its Products. 

whirled again at full speed for one minute, and hot water 
added a second time, until the lower part of the column of 
fat comes within the scale on the neck of the test bottle, 
preferably to the 1 or 2 per cent, mark, so as to allow for 
the sinking of the column of fat, owing to the gradual cool- 
ing of the contents of the bottle. By dropping the water 
directly on the fat in the second filling, the column of 
fat will be washed free from light flocculent matter, which 
might otherwise be entangled therein and render the read- 
ing uncertain or even too high. A final whirling for one 
minute completes the separation of the fat. 

37. Measuring the fat. The amount of fat in the neck 
of the bottle is measured by the scale or graduations on 
the neck. Each division of the scale represents two-tenths 
of one per cent, of fat, and the space which the fat occupies 
shows the per cent, of butter fat contained in the sample 
tested. 

The fat obtained should form a clear yellowish liquid dis- 
tinctly separated from the acid solution beneath it. There 
should be no black or white sediment in or below the col- 
umn of fat, and no bubbles or foam on its surface. The 
bottles should be kept warm until the readings are made, so 
that the column of fat will have a sharply defined upper and 
lower meniscus. 

The fat is measured from the lower line of separation be- 
tween the fat and the water, to the top of- the fat column, 
at the point 5, shown in the figure 10, the reading being thus 
taken from a to h^ and not to c or to d. Comparative grav- 
imetric analyses have shown that the readings obtained in 
this manner give correct results. While the lower line of 
the fat column is nearly straight, the upper one is curved, 



The Babcock Test. 



33 



a 



and errors in the reading of the column are therefore easily 
made, unless the preceding rule is observed. 

The readings should be made when 
the fat has a temperature of about 
140° F., although the results obtained 
will not be appreciably affected if the 
temperature falls below 120°. The 
fat separated in the Babcock test 
solidifies at about 100^ F. No read- 
ings should be attempted if the fat is 
partly solidified, as it is impossible to 
get an accurate reading in this case.* 
A pair of dividers will be found 
convenient for measuring the fat, 
and the liability of error in reading 
is decreased by their use. The points 
of the dividers are placed at the up- 
per and lower limits of the fat column 
(from a to 6 in fig. 10). The dividers 
are now lowered, one point being placed at the zero mark 
of the scale, and the mark at which the other point touches 
the scale will then show the per cent, of fat in the sample 
tested. 



=— 



Fig. 10. Measuring the col- 
umn of fat in a Babcock 
test bottle. 



* The effect of differences in the temperature of the fat on the readings ob- 
tained will be seen from the following: If 110 and 1£0° F. be taken as the extreme 
temperatures, at which readings are made, this difference of 40° F. (22.3° C) would 
make a difference in the volume of the fat column obtained in case of 10 per cent, 
milk, of .00064 x 2 x 22.3 = .028544 cc. or .14 per cent., .0C064 being the expansion 
coetficient of pure butter fat per degree Centigrade between £0 and 100° C. {Zune, 
Analyse des Beurres, I, 87), and 2, the volume of the fat in cc. contained in 17.6 cc. of 
10 per cent. milk. On 5 per cent, milk this extreme difference would therefore be 
about .07 per cent., or considerably less than one-tenth of one per cent. 
3 



34 Testing Milk and Its Products, 

B. — Discussion of the Details of the Babcock Test. 

38. Although the manipulations of the Babcock test are 
few and comparatively simple, various difficulties ma}^ be 
met with in using it, particularl}' in the hands of beginners. 

The main points that have to be observed as to apparatus 
and testing materials in order to obtain correct and satisfac- 
tory results by this test will now be considered, and such 
suggestions and help offered, as has been found desirable 
from an extensive experience with a great variety of milk 
samples, apparatus, and accessories. 

1. — Glassware. 

39. Test bottles. When 17.6 cc, or 18 grams of milk, 
are measured into the Babcock test bottle, the scale on the 
neck of the bottles shows directh^ the percent of fat found 
in the milk. The scale is graduated from to 10 per cent. 
10 per cent, of 18 grams is 1.8 grams. As the specific gravity 
of pure butter fat (i. e. its weight compared with that of an 
equal quantity of pure water) at the temperature at which 
the readings are made (about 120° F.), is 0.9, 1.8 grams of 
fat will occupy a volume of -g = 2 cubic centimeters. The 
space between the and 10 per cent, marks on the necks of 
the test bottles must therefore hold 2 cc, if correctly made. 
The scale is divided into 10 equal parts, each part repre- 
senting one per cent., and each of these are again sub-divid- 
ed into five equal parts. Each one of the latter divisions 
therefore represents two-tenths of one per cent, of fat when 
17.6 cc. of milk is measured out. The small divisions are 
sufficiently far apart in most Babcock test bottles to make 
possible the estimation of one-tenth of one per cent, of fat 
in the samples tested. 



The Bahcock Test. o^ 

The figures and lines of the measuring scale become in- 
distinct by use; the black color may be restored by rubbing 
a soft lead pencil over the scale, or by the use of a piece of 
burnt cork after the scale has been rubbed with a little 
tallow. On wiping the necks with a cloth, or a piece of paper, 
the black color will show in the etchings of the glass, mak- 
ing these plainly visible. 

40. The test bottles should have a capacity of about 
50 cc, or less than two ounces; they should be made of 
well-annealed glass that will stand sudden changes of tempe- 
rature without breaking, and should be sufficiently heavy to 
withstand the maximum centrifugal force to which they are 
likely to be subjected in making tests. This force may not 
on the average be very far from 30.G5 lbs. (see 57) or the 
pressure exerted in whirling the bottles filled with milk 
and acid, in a centrifugal machine of IS inches diameter, 
at a speed of 800 revolutions per minute. 

Special forms of test bottles used in testing cream and 
skim milk are described under the heads of cream- and 
skim milk testinor. 

41. Marking test bottles. Test bottles can now be 
bought with a small band or portion of their neck or body 
ground or "frosted," for numbering the bottles with a lead 
pencil. Bottles without this ground label can be roughened 
at any convenient spot by using a wet fine file to rub ofl^ the 
smooth surface of the glass. There is this objection to the 
latter method that unless carefully done, it is apt to weaken 
the bottles so that they will easily break, and to both meth- 
ods, that the lead pencil marks made on such ground labels 
are easily erased during the test, unless the bottles are 
carefully handled. Small strips of tin or copper with a 



36 Testing Milk and Its Products. 

number stamped thereon are sometimes attached as a collar 
around the necks of the bottles. They are, however, easily 
lost, especially when the top of the bottle is slightly broken, 
or at any rate, are soon corroded so that the numbers can 
onl}^ be seen with difficulty. 

The best and most permanent label for test bottles is 
made by scratching a number with a marking diamond into 
the glass directlj^ above the scale on the neck of the bottles. 
In ordering an outfit, or test bottles alone, the operator may 
specify that the bottles are to be marked 1 to 2\^ or as many 
as are bought, and the dealer will then put the numbers on 
with a marking diamond. A careful record should be kept 
of the number of the bottle into which each particular sam- 
ple of milk is measured. Mistakes are often made when 
the operator trusts to his memory for locating the different 
bottles tested at the same time. 

42. Cleaning test bottles. The fat in the neck of the 
test bottles must be liquid when these are cleaned. 
The bottle should be shaken in emptying the acid, in order 
to remove the white residue of sulfate of lime, etc., from 
the bottom ; if the acid is allowed to drain out of the bottle 
without this being shaken during the emptying, this residue 
will be found to stick very tenaciously to the bottom in the 
subsequent cleaning with water. 

A convenient method of emptying the test bottles Is 
shown in the illustration (fig. 11). After reading the fat, 
the bottles are taken from the tester and placed, neck down, 
in the \ inch holes of the board cover of a five-gallon stone- 
ware jar. An occasional shaking while the liquid is running 
from the bottles will rinse off the precipitate of sulfate of 
lime. A thorough rinsing with boiling hot water by means 



The Babcock Test. 



37 




of an apparatus, devised bj- one of us* (see fig. 12) is gen- 
erally sufficient to remove all grease and dirt, as well as 

acid solution, 
jili^WI^^^Ri from the inside 

of the bottles. 
When the bottles 
have been rinsed, 
the}' are placed 
in an inverted po- 
sition to drain, on 
a galvanized iron 
rack, as shown in 
fig. 13, where 
they are kept un- 
FiG. 11. v/aste acid jar. til needed. The 

outside of the bottles should occasionally be wiped clean 
and dr}'. 

43. The amount of unseen fat that clings to glassware 
is generally not sufficient to be noticed in the results ob- 
tained in testing whole milk, but it plays an important part 
in testing samples of separator skim milk. It may be readily 
noticed by making a blank test with clean water in bottles 
which have been used for testing ordinary milk, and have 
been cleaned by simply draining the contents and rinsing 
once or twice with hot water; at the conclusion of the test the 
operator will often find that a few drops of fat — sometimes 
enough to condemn a separator — will collect in the neck 
of the bottles, although the water tested has not been near 
a separator. 

Boiling hot water will generally clean the grease from 
glassware for a time, but all test bottles should, in addition, 



* Farrington. 



38 



Testing Milk and Its Products. 



be given an occassional bath in some weak alkali, or other 
grease-dissolving solution. Persons doing considerable 
milk testing will find it of advantage to provide themselves 
with a small copper tank, which can be filled with a weak 
alkali-solution (figs. 14 and 15). After having been rinsed 




Fig. 12. Apparatus for cleaning test bottles. A, apparatus in position; the 
water flows from the reservoir through the iron pipe h into the inverted test bot- 
tle d through the brass tube c, screwed into the iron pipe. B shows construction 
of the rubber support on which the top of the test bottle rests; /, draining sink. 

with hot water, the test bottles are placed in the hot solu- 
tion kept in the tank, where they may be left completely cov- 
ered with the liquid. If the tank is provided with a small 



The Bahcock Test. 39 

faucet at the bottom, the liquid can be drawn otf when the 
test bottles are wanted. A tablespoonful of Savogran to 
about two gallons of water will make a very satisfactory 
cleaning solution; sal soda, Gold Dust, Lewis lye or Babbitt's 
potash are equally efficient. The cleansing properties of 
solutions of an}^ of these substances are increased by warm- 
ing the liquid. The test bottles must be rinsed twice with 
hot water after they are taken from this bath. 




F^G. 13. Draining-rack for test bottles. 

The black stains that sometimes stick to the inside of test 
bottles after prolonged use, can be removed with a little 
muriatic acid. 

44. Pipette. The difference in the weights of various 
samples of normal milk generally falls within comparatively 
narrow limits: if a given quantit}^ of water weighs 1 pound, 
the same quantity of the usual grades of normal milk will 
weigh from 1.029 to 1.033 pounds, or on the average 1.03 
lbs. 18 grams* of water measures 18 cc; 18 grams of 



* Cubic centimeters (abbreviated: ce.) are the standard used for measuring 
volume in the metric system, similar to the quart or pint measure in our ordinary 
system of measures. 1 quart is equal to a little more than 1000 cubic centimeters. 
Tn the same way, grams represent weight, like pounds and ounces. 1 cc. of 
water at 4° Centigrade weighs 1 gram. 1000 grams (= 1 kilogram) is equal to 2.2 lbs. 
Avoir. (See Appendix, for Comparisons of Metric and Customary Weights and 
Measures). 



40 



Testing Milk and Its P7'oducts. 



milk will therefore take up a smaller volume (measure less) 
than 18 cc, viz: 18 divided by 1.03, which is very nearly 

17.5. This is the 
quantity of milk 
taken in the Bab- 
cock test. A certain 
amount of milk will 
adhere to the walls 
of the pipette when 
it is emptied, and 
this thin film has 
been found to weigh 
about one-tenth of 
a gram; conse- 
quently 17.6 cc. has 
been adopted as the 
capacity of the pip- 
ette used for deliv- 
ering 18 grams of 

Fig. 14. Tank for cleaning test bottles. milk. 

For convenience in measuring the milk, the 
shape of the pipette is of importance. The 
mark on the stem should be two inches or more 
from the upper end of the pipette. The lower 
part should be small enough to fit loosely into 
the neck of the test bottle, and not contracted 
to a fine hole at the point; the point should be 
large enough to allow a quick empt3ing of the 

' -r,. -, ox Fig. 16. Pip- 

pipette. (Fig. 16). ettepoints- 

45. Fool pipettes. Soon after the Babcock test A, proper con- 
V , , 11 1 J • struction; B, 

began to be generally used at creameries as a means , irable 

of paying for the milk, a creamery supply house put construction. 





The Bahcock Test. 



41 



on the market a 20 cc. milk-measuring pipette, which was 
claimed to show the exact butter value of milk, instead 
of its content of butter fat, as in the case in using the 
ordinary 17.6 cc. pipette. A 20 cc. pipette will deliver 2.4 cc, or 
13.6 per cent, more milk than a 17.6 cc. pipette, and it follows 
that the results obtained by measuring out milk for Babcock tests 
with these pipettes will be about 13.6 per cent, too high. In con- 
sidering the subject of Overrun it is noted that the excess of butter 
yield over the amount of fat contained in a certain quantity of 
milk will range from about 10 to 15 per cent., or on the average 
12-13 per cent. The 20 cc. pipntes may, therefore, give approxi- 




FiG. 15. Rack for holding test bottles in tank shown in fig. 14. 
mately the yield of butter obtained from a quantity of milk, but 
as will be seen, this yield is variable, according to the skill of the 
butter maker, and according to conditions beyond his control, 
and cannot therefore be used as a standard in the same manner as 
the fat content of the milk. Similar 22 cc. pipettes were also sent 
out. These pipettes created a great deal of confusion during the 
short time they w^ere on the market, and were popularly termed 
^'fool pipettes," as the tests obtained bj' them did not give, what 
they professed to do, an accurate and definite measure of the but- 
ter-producing qualities of different lots of milk. It is not known 
that any of these pipettes are on the market at the present time. 



42 Testing Milk and Its Products. 

46. Acid measures. A 17.5 cc. glass cylinder for 
measuring the acid is generally included in the outfit, when 
a Babcock tester is bought. This cylinder answers every 
purpose if only occasional tests are made; the acid is poured 
into the cylinder from the acid bottle, as needed, or a quan- 
tity of acid sufficient for the number of test bottles to be 
whirled at a time, is poured into a small glass beaker, pro- 
vided with a lip, or into a porcelain pitcher; these may be 
more easily handled than the heavy acid bottle, and the acid 
measure is then filled from such a vessel. 

Where a considerable number of tests are made regularly, 
the acid can be measured into the test bottles faster and^ 
with less danger of spilling, by using some one of the many 
devices proposed for this purpose. There is some objection 
to nearly all of these appliances, automatic pipettes, buret- 
tes, etc., although they will often give good satisfaction for 
a time while new. Sulfuric acid is so corrosive, and opera- 
tors as a rule take such poor care of such apparatus, that it 
is a very difficult matter to design a form which will remain 
in good wording order for any length of time. Automatic 
pipettes attached to acid bottles or reservoirs, to prove 
satisfactory, must be made entirely of glass, and strong, of 
simple construction, tightly closed and quickly operated. 

47. The Swedish Acid Bottle answers these requirements- 
better than any other device for this purpose known to the 
writers at the present time. Its use is easily understood (see 
fig. 17) ; it gives good satisfaction if the hole in the glass 
stop cock through which the acid passes has a diameter of 
at least one- eighth of an inch, as is generally the case. We 
have used or inspected some half a dozen other devices, 
which have been placed on the market by various dealers 



The Bahcock Test. 



43 




for delivering the acid, but cannot recommend them for use 
in factories, or outside of chemical laboratories. 

48. Instead of measuring out the acid, Bartlett* re- 
cently suggested adding it directly to the milk in the test 
bottles, till the mixture rises to a mark 
on the body of the bottle at the point 
where this will hold 37.5 cc, i. e., the 
total volume of milk and acid (74). 
This method of adding the acid is in 
the line of simplicity and may in time 
become generally adopted. The marks 
should, however, be put on by the man- 
ufacturers, as the operator in attemping 
to do so will be apt to weaken or break 
the bottles. 

Fig. 17. Swedish acid 

Calibration of glassware. 1. — Test bottle; the side-tube is 

made to hold 17.5 cc. of 

BOTTLES. The Babcock milk test bot- ^cid. 
ties are so constructed that the scale or graduation of the 
neck measures a volume of 2 cubic centimeters, between 
the zero and the 10 per cent, marks (39). The correctness 
of the graduation may be easily ascertained by one of the 
following methods: 

49. Calibration with mercury. 27.18 grams of metallic 
mercury are weighed into the perfectly clean and dry test 
bottle; since the specific gravity of mercury is 13.59, double 
this quantity will occupy a volume of exactly 2 cubic centi- 
meters (44*). The neck of the test bottle is then closed 
with a small smooth and soft cork, or a wad of absorbent 
cotton, cut off square at one end, the stopper being pressed 
down to the first line of the graduation. The bottle is now 



Maine experiment station, bull. No. 31. 



44 Testing Milk and Its Products. 

inverted so that the mercury will run into its neck. If the 
total space included between the and 10 marks is just 
filled with the two cubic centimeters of mercury, the grad- 
uation is correct. Bottles, the whole length of the scale of 
which vary more than two-tenths of one per cent, are inac- 
curate, and should not be used. 

The mercury may be conveniently transferred from one 
test bottle to another, by means of a thin rubber tube which 
is slipped over the end of the necks of both bottles, and one 
weighing of mercury will thus suffice for a number of cali- 
brations. In transferring the mercury, care must be taken 
that none of it is lost, and that small drops of mercury are 
not left sticking to the walls of the bottle emptied. A 
sharp tap on the bottle with a lead pencil will help to 
remove minute drops of mercury from the inside of it. 
Unless the bottles to be calibrated are thoroughly cleaned 
and dry, it is impossible to transfer all the mercury from 
one bottle to another. 

After several calibrations have been made, the mercury 
should be weighed again in order to make certain that none 
has been lost by the various manipulations. The scale, fig. 
28, shown in (84) is sufficiently delicate for making these 
weighings. 

50. Cleaning mercury. Even with the best of care, mer- 
cury used for calibration of glassware will gradually become 
dirty so that it will not flow freely over a clean surface of 
glass. It may be cleaned from mechanical impurities, dust, 
films of grease, water, etc., by filtration through heavy filter 
paper. This is folded the usual way, placed in an ordinary 
glass funnel and its point perforated with a couple of pin 
holes. The mercury will pass through in fine streams, leav- 
ing the impurities on the filter paper. Mercury may be 



The Bahcock Test. 45 

freed from foreign metals, zinc, lead, etc., sometimes noticed 
as a grayish, thin film on its surface, by leaving it in 
contact with common nitric acid for a number of hours; the 
mercury is best placed in a shallow porcelain or granite ware 
dish and the nitric acid poured over it, the dish being cov- 
ered to keep out dust. The acid solution is then carefully 
poured off and the mercury washed with water; the latter is 
in turn poured off, and the last traces of water absorbed by 
means of heavy clean filter paper. 

The mercury to be used for calibration of glassware should 
be kept in a strong bottle, closed by an ordinary stopper. 
In handling mercury, care must be taken not to spill any 
portion of it; finger-rings should be removed when calibra- 
tions with mercury are to be made. 

Mercury forms the most satisfactory and accurate ma- 
terial for calibration of test bottles, on account of its heavy 
weight and the ease with which it may be manipulated. 
Equally correct results may, however, with proper care be 
obtained by using one of the following methods: 

Calibration with water. This may be done by means of a 
delicate pipette or burette, or by weighing in a somewhat 
similar manner, as explained in case of calibration with 
mercury. 

51. Si, Measurivg the water. Fill the test bottle with 
water to the zero mark of the scale; remove any surplus 
water and dry the inside of the neck with a piece of filter 
paper or clean blotting paper; then measure into the bottle 
2 cc. of water from an accurate pipette or a burette, divided 
to 20 of a cubic centimeter. If the graduation is correct, 
2 cc. will fill the neck exactly to the 10 per cent, mark of 
the scale. 



46 Testing Milk and Its Products. 

52. b, Weighing the water. Fill the bottle with water 
to the zero mark of the scale and remove any surplus 
water in the neck, as before. Weigh the bottle with the 
water contained therein. Now fill the neck with water to 
the 10 per cent, mark, and weigh again. The difference be- 
tween these weights should be 2 grams. 

In all cases when calibrations are to be made, the test 
bottles, or other glassware to be calibrated, must be 
thoroughly cleaned with strong sulfuric acid, or soda lye, 
and washed repeatedl}^ with pure water, and dried. Grlass- 
ware is not clean unless water will run freely over its sur- 
face, without leaving any adhering drops. 

53. Intermediate divisions. The space between and 10 
on the scale of the Babcock test bottle is divided into 50 
divisions, each five of which, as previously shown (39) 
representing 1 per cent. Since these intermediate divisions 
are generally paade with a dividing machine, they are as a 
rule correct, but it has happened that the divisions have 
been inaccurately placed, although the space between and 
10 was correct. The accuracy of the intermediate divisions 
can be ascertained by sliding along the scale a strip of 
paper upon which has been marked the space occupied by 
one per cent., and compare the space with those of each 
per cent, on the scale. 

54. 2. — Pipette and acid cylinder. The pipette and 
the acid cylinder used in the Babcock test ma}^ be calibrated 
by any of the methods already given. Sufficiently accurate 
results are obtained by weighing the quantity of water 
which each of these pieces of apparatus will hold, viz: 17.6 
grams and 17.5 grams, respectively. The necessity of pre- 
vious thorough cleaning of the glassware is evident from 



The Babcock Test. 47 

what has been said in the preceding. The pipette and the 
acid measure ma}' be weighed empt}' and then again when 
filled with pure water to the mark, or the measureful of 
water may be emptied into a small weighed vessel, and this 
weighed a second time, In either case the weight of the 
water contained in the pipette or the acid measure is ob- 
tained by difference.* 

Calibrations of the acid cylinder are generally not called 
for, except as a laborator}- exercise, since small variations 
in the amount of acid measured out do not affect the accu- 
racy of the test. 

2. — Centrifugal Machines. 

55. The capacity of the testing machine to be selected 
should be governed by the number of tests which are likely 
to be made at one time. For factory purposes a twentj^-five 
to thirty bottle tester is generally large enough, even if 
toward a hundred samples of milk are to be tested at a 
time. The operator can use his time more economically 
in running a machine of this size than one holding fift}' or 
sixt}' bottles; the work of filling or cleaning the bottles and 
measuring the fat can be done while the centrifuge is run- 
ning if a double suppl}^ of bottles are at hand. Large test- 
ers require more power than smaller ones, and when sixt}' 
tests are completed, man}' of the bottles will cool, and the 
fat column crystalize, before the operator has time to read 
them, unless special precautions are taken for keeping the 
bottles warm. 



* 1 cubic centimeter of distilled water weighs 1 gram, when weighed in a vacuum 
at the temperature of the maximum density of water (4° C); for the purposes of 
calibration of glassware used in the Babcock test, sufficiently accurate results are, 
however, obtained by weighing the water in the air and at a low room temperature 

(60° F.) 



48 Testing Milk mid Its Products. 

56. The tester should be securely fastened to a solid 
foundation and set so that the revolving wheel is level. The 
latter must be carefully balanced in order that the tester 
may run smoothly at full speed when empty. A machine 
that trembles and shakes when in motion is neither satis- 
factory nor safe, and the results obtained are apt to be too 
low. High -standing machines are more apt to cause trou- 
ble in this respect than low machines, and should therefore 
be subjected to a severe test before they are accepted. 

If all the sockets are not filled with bottles when a test 
is to be made, the bottles must be placed diametrically op- 
posite one another so that the machine will be balanced 
when run. The bearings should be kept cleaned and oiled 
with as much care as the bearings of a cream separator. 

The cover of the machine should always be kept on while 
the bottles are whirled, and should not be removed until the 
machine stops; the cover should be tight-fitting and may be 
fastened with hooks soldered on the side of the machine; 
test bottles have sometimes been broken while the machine 
has been running at full speed, and every possible precau- 
tion should be taken to protect the operator from any dan- 
ger from spilled acid or broken glass. 

57. Speed required for the complete separation of 
the fat. There is a definite relation between the diameter 
of the Babcock testers and the speed required for a perfect 
separation of the fat. In the preliminary work with the 
Babcock test the inventor found that with the machine used, 
the wheel of which had a diameter of eighteen inches, it 
was necessary to turn the crank, so as to give the test bot- 
tles seven to eight hundred revolutions per minute, in order 
to effect a maximum separation of fat; later work has 



The Babcock Test. 49 

shown that this speed is ample. Taking therefore this 
as a standard, the centrifugal force to which the con- 
tents of the test bottles are subjected when supported on 
an eighteen inch wheel and turned 800 revolutions per 
minute, can be calculated as follows : 

The centrifugal force, F, acting on the bottles is expressed by the 
formula 

F= ^-^^ a) 

32.2r ^ 

in which w = the weight of the bottle with contents, in pounds ; 
Y = the velocity, in feet per second, and r = the radius of the 
wheel, in feet. 

When the wheel is turned 800 times a minute, a bottle supported 
on its rim will travel 2 TTr X '6%'' = 2X 3.1415 X A X «6'd' = 62.83 
feet per second. The weight of a bottle, with milk and acid, is 
very near 3 ounces, or /e of a pound. Substituting these values 
for V and w, gives 

p^ h X 62.83^ =30.65 lbs. 
32.2 X h 

The bottles are therefore, under conditions given, subjected to a 
pressure of 30.65 lbs. In order to calculate the speed required 
for obtaining this force in case of machines of other diameters, 
the value of v in formula (I) is found from 



^ ^/ 32.2 F X r 



w^ 
Substituting the values for F and w, 



(11) 



v== |/32.2 X 30.65r _ ^^^^^ 
h 
In this equation the values r = 5, 6, 7, . . . 12 inches are 
substituted in each case (i\, ^^, ^^, • • • if feet), and the velo- 
city in feet per second then found at which the bottles are whirled 
when placed in wheels of diameters 10 to 24 inches, and subjected 
in each case to a centrifugal force of 30,65 lbs. As the number of 

60 r 
revolutions per minute = -75 , v being as before the velo- 

4 



50 Testing Milk and Its Products. 

city in feet per second, and r the radius of the wheel, the speed at 
which the wheel must be turned, is found by substituting for v the 
values obtained in the preceding calculations in case of wheels of 
different diameters. The results of these calculations are given in 
the following table: 



Diameter 
)/ wlieel, d 






Velocity in feet 
per second, v. 


Number of revolutions of 
whet I, per minute, 


10 






46.84 




1074 


12 






51.31 




980 


14 






55.43 




909 


16 






59.26 




848 


18 






62.84 




800 


20 






66.24 




759 


22 






69.47 




724 


24 






72.56 




693 


These 


figures 


show 


that a tester, for 


instance. 


25 inches in 



diameter, requires less that 700 revolutions per minute for a per- 
fect separation of the fat in Babcock bottles, while a ten-inch tes- 
ter must have a speed of nearly 1100 revolutions, in order to 
obtain the same result. 

58. To find the number of turns of the handle corres- 
ponding to the number of revolutions made by the wheel, 
the handle is given one full turn, and the number of times 
which a certain point or part of the wheel revolves, is noted. 
If the wheel has a diameter of 20 inches, and revolves 12 
times for one turn of the handle, the latter should be turned 
-^2^=63 (see table), or about once every second, in order to 
effect a maximum separation of fat. By counting the num- 
ber of revolutions, watch in hand, and consulting the pre- 
ceding table, the operator will soon note the speed which 
must be maintained in case of his particular machine. It is 
vitally important that the required speed is always kept up; 
if through carelessness, worn-out or dry bearings, slipping 
belts, etc., the speed is slackened, the result will come too 



The Bahcock Test, 51 

low; it may be a few tenths, or even more than one percent. 
Care as to this point is so much the more essential as the 
results obtained by too slow whirling may seem to be all 
right, a clear separation of fat being often obtained even 
when the fat is not completely separated. 

59. Ascertaining the necessary speed of testers. In 

buying a tester the operator should first of all satisfy himself 
at what speed the machine must be run to give correct results ; 
the preceding table will serve as a guide on this point. He 
should measure out a dozen tests of the same sample of 
milk, and whirl half the number at the speed required for 
machines of the diameter of his tester. Whirl the other 
half at a somewhat higher speed. If the averages of the 
two sets of determinations are the same, within the probable 
error of the test (sa}^, less than one-tenth of one percent.) 
the first whirling was sufficient, as it is believed will gener- 
ally be the case. If the second set of determinations come 
higher than the first set, the first whirling was too slow, and 
a new series of tests of the same sample of milk should 
be made to ascertain that the second whirling was ample. 

This method will test not only the speed required with 
the particular machine at hand, but will also serve to indi- 
cate the correctness of the calibration of the bottles. A 
large number of tests of the same sample of milk made as 
directed (pouring the milk once or twice previous to taking 
out a pipetteful for each test) should not vary more than 
three-tenths of one percent, at the outside, and in the hands 
of a skilled operator will come within two-tenths of one per- 
cent. If greater discrepancies occur, the test bottles giving 
too high or too low results should be further examined, and 
<5alibrated according to the directions already given (49). 



52 



Testing; Milk and Its Products. 



60. Hand testers. When only a few tests are made 
at a time, and at irregular intervals, as in case of dairymen 
who test single cows in their herds, a small hand tester 
answers every purpose. These may be had in sizes from 
two to twelve bottles. In selecting a particular make of 
tester the dairymen has the choice of a large number of 
difierent kinds of machines. It is a source of regret that 
most of the machines placed on the market for this purpose 
in the past have been so cheaply and poorly constructed as to 
prove very unsatisfactory after having been in use for a time. 
The sharp competition between manufacturers of dairy 
supplies, and the clamor of dairymen for something cheap, 

fully account for 
this condition of 
affairs. This ap- 
plies especially to 
the many machines 
made with belts or 
friction application 
of power. The 
main objection to 
these machines is 
the uncertainty of 
the speed obtained, 
when they have 
been in use for some time, and the belt or friction appliance 
begins to slip. Hand testers made with cog gear wheels 
are more to be depended on for giving the necessary speed 
than belt or friction machines; they are generally noisy, 
but the bottles are always whirled at the speed which the 
number of turns made by the crank would indicate. 




Fig. 18. " No-tin '' test. 



The Babcock Test. 



53 



The " No-tin " test (see fig. 18) is, in the opinion of the 
authors, worthy of special mention among the hand testers 
made at the present time; it is a six-bottle geared machine, 
durable of construction, and runs smoothly and without 
noise. 

61. Power testers. For factory purposes, steam tur- 
bine machines (fig. 19) are most satisfactory when well made 
and well cared for. They should always be provided with 
a speed indicator and steam gauge, both for the purpose of 
knowing that sufficient speed is attained, and also to pre- 
vent what may be serious accidents from a general smash- 
up, if the turbine ''runs wild" by turning on too much 
steam. The revolving wheel of the tester should be made 
of wrought or malleable iron, or of wire, so that it will not 

be broken by 
the centrifu- 
gal force, thus 
avoiding seri- 
ous accidents. 
The swinging 
pockets which 
hold the test 
bottles in some 
machines, 
should be so 
made that the 

bottles will not strike the center of the revolving frame 
when in a horizontal position. Tests have often been lost 
by the end of the neck catching at the center, the bottles 
thus failing to take an upright position when the whirling 
stops. 




Fig. 19. Type of Babcock steam turbine testers. 



54 Testing Milk and Its Products. 

3. — Sulfuric Acid. 

62. The sulfuric acid to be used in the Babcock test 
should have a specific gravity of 1.82-1.83.^ The com- 
mercial oil of vitriol which can be bought for about 
2 cents a pound in carboy lots, is commonly used. One 
pound of acid is sufficient for fifteen tests. The acid should 
be kept in stoppered glass bottles, preferably glass or rub- 
ber stoppered ones, since a cork stopper is soon dissolved 
by the acid and rendered useless. If the bottle is left uur 
corked, the acid will absorb moisture from the air and will 
after a time become too weak for use in this test. Lead is 
the only common metal which is not dissolved by strong 
sulfuric acid; where considerable milk testing is done, it is 
therefore desirable to provide a table covered with sheet 
lead on which the acid may be handled. 

63. The acid dissolves iron, tin, wood and cloth, and 
burns the skin. If acid is accidently spilled, plenty of water 
should be used at once to wash it off. Ashes, potash, soda, 
and ammonia neutralize the action of the acid, and a weak 
solution of any one of these alkalies can be used after the 
acid has been washed off with water. The red color caused 
by the action of the acid on clothing can be removed by 
wetting the spot with weak ammonia water; the ammonia 
must, however, b*e applied while the stain is fresh, and is in 
its turn washed off with water, 

64. Testing the strength of the acid. The strength 
of the acid can be easily tested by the use of such a balance 
as shown in fig. 27 (84). A dry test bottle is weighed, and 



* A specific gravity of 1.82 means that any given volume of the acid weighs 
1.82 times as much as the same volume of water at the same temperature (see also 
under Lactometer, 94), 



The Bahcock Test. 



55 



then filled with acid exactly to the zero mark, or to any other 
particular line of the scale. It is then again weighed accurate- 
ly; the difference between these two weights will give the 
weight of the acid in the bottle. Next empty the bottle and 
rinse it thoroughly with water (until the water has no longer 
an acid taste); fill the bottle with water to the same line as be- 
fore and weigh; the difference between this weight and that 
of the empty bottle gives the weight of the same volume of 
water as that of the acid weighed. Divide the weight ot the 
acid by the weight of the water; the quotient gives the spe- 
cific gravity of the acid. If this is between 1.82 and 1.83, 
the strength of the acid is correct. The outside of the test 
bottle should always be wiped dry before the liquids are 
weighed in it. Unless great care is taken in measuring out 
the acid and the water, and in weighing both these and the 
test bottle, the results obtained will not be trustworthy. 

65. Too strong acid can sometimes be successfully used 
by taking less than the required amount of each test, e. g. 
about 15 cc. Operators are warned against reducing the 
strength of the acid by adding water to it, as accidents are 
very apt to occur when this is done. A too strong acid can, 
if desired, be weakened by si m plying leaving the bottle 
which holds it, uncorked for a time; or by pouring the acid 
into a bottle containing a small quantity of water; in the 
latter case, the first portions of acid should be added care- 
fully, a little at a time, shaking the bottle after each addi- 
tion, so as not to cause it to break from the great heat 
evolved in mixing the acid and the water. Never dilute acid 
hy pouring water into it. 

66. If the acid is too weak, correct results may some- 
times be obtained by using more than the specified quantity, 



56 



Testing Milk and Its Products. 



say 20 cc. If a good test is not obtained with this quantity 
of acid, a new lot must be secured, as its specific gravity in 
such a case must be below 1.82. The observing operator 
will soon be able to judge of the strength of the acid by 
its action on milk in mixing the two liquids in the Babcock 
test bottles; it is indeed remarkable what slight differences 
in the specific gravity of the acid will make themselves 
apparent in working the test, as regards the rapidity with 
which both the curdled milk is dissolved, and the mixture 
of acid and milk turns black. 

67. The relation between the strength of sulfuric acid 
and its specific gravity will be seen from the following table: 

Strength of Sulfuric Acid {Lunge and Isler, 1890). 



Sulfuric Acid 

97 per cent. 

96 

95 

94 

93 

92 

91 

90 

89 

88 



Specific Gravity 
(15° C,u-aier4° C). 

1.841 
1.840 
1.839 
1.837 
1.834 
1.830 
1.825 
1.820 
1.815 
1.808 



It will be noticed that the sulfuric acid to be used in the 
Babcock test should contain 90 to 92 per cent, of acid 
(H2SO4); slightly weaker or stronger acid than this may, as 
previously stated, be used by adjusting the quantity of acid 
taken for each test to the strength of the acid, but success- 
ful tests cannot be made with acid weaker than 89 per cent, 
or stronger than 95 per cent. 



H 



The Babcock Test. 57 

68. The Swedish acid tester (fig. 20) is a small hy- 
drometer, intended to show whether the acid to be used in 
the Babcock test is of the correct strength. We 
have examined a number of these testers, and have 
found them practicall}^ useless for the purpose in- 
tended. The reason for this lies in insufficient 
•ij sensitiveness in the instrument; while the testers 
1 examined were found to sink to the line marked 
Correct on the scale, when lowered into sulfuric acid 
of a specific gravity of 1.83, they would sink to a 
point much nearer the same mark when lowered 
into either too strong or too weak acid, than to the 
lines marked Too strong or Too weak^ respectively. 

An examination of the proportionate parts of the 
testers shows that such must be the case: The total 
weight of the testers varies between 7 and 8 grams ; the 
diameter of the stem is nearly 5 millimeters, and the dis- 
tance between the two lines marked Too strong and Too 
weak is 13.5 millimeter. A good hydrometer, such as 
used in chemical laboratories for determining the spe- 
Swedisli ^^^^ gravity of liquids of 1.8 to 2.0, weighs about 75 
acid tester, grams; the diameter of the stem is 6 mm., and the dis- 
tance between the 1.82 and l.Si marks on the scale is 
15.5 mm. ; these limits may be taken to represent too 
weak and too strong acid, respectively. Comparying now 
this hydrometer with the Swedish tester, the weight of the for- 
mer would make it ten times as sensitive as the latter, if the size 
of the stem was the same in either case; as it is, the tester has the 
advantage in point of thinness of stem (see 94), as the volumes of 
the same lengths of stem in the two instruments ate as the square 
of their diameters, i. e., as 25:36. This means that the Swedish tes- 
ters are onh^ =: _ as sensitive as the hydrometer, or a 

•^ 10 X 25 7 ^ 

•diiference on the scale of the latter amounting to 15.5 mm. (see 



^8 Testing Milk and Its Products. 

above), would represent only 2.2 mm., on the scale of the Swedish 
tester. The line marked Too strong must therefore be only 1.1 
mm. (2V of an inch) below the Correct line; and that marked Too^ 
weak the same distance above the line. But this is too small a 
distance to be differentiated by persons unfamiliar' with the use of 
delicate hydrometers, especially since the meniscus of the liquid 
formed around the stem of the tester renders an accurate reading 
somewhat difficult. 

The Swedish acid tester can be made more delicate by changes 
in one or two directions: by making the bulb larger, thus necessi- 
tating an increase in weight, or by making the stem thinner. By 
way of comparison it maybe stated that the hydrometers used for 
determining the specific gravity of the ether-fat solution in Sox- 
hlet's areometric method of milk analysis have a stem only 2 mm. 
in diameter, and the distance of the scale between .765 and .745 is 
70 mm., or 2% inches. 

Even if these testers are changed as suggested, their practicabil- 
ity still remains an open question. The action of sulfuric acid of 
different strength is very characteristic (66), and in the hands of 
experienced operators, is as delicate an index to the strength of 
the acid as can be desired, making rather unnecessary a separate 
instrument for ascertaining the correctness of the strength of the 
acid used in milk testing. 

69. The color of the fat column an index to the 
strength of the acid used. The strength of the acid is 
indicated to a certain extent by the color of the fat which 
separates in the neck of the test bottle when milk is 
tested. If the directions given for making the test are care- 
fully followed, the fat separated out will be of a golden 
yellow color. If the fat is light colored or whitish, it gen- 
erally indicates that the acid is too weak, and a dark colored 
fat, with a layer of black material beneath it, shows that the 
acid is too strong. 

The strength of the acid used in the test is not sufficient 
at ordinary temperatures of testing to appreciably dissolve 



The Babcock Test, 59 

the fat, but a variation in the strength of the acid or in the 
temperature of the milk influences the intensity of the ac- 
tion of the acid on the fat, as shown in the color of the fat 
obtained. 

The following experiment shows the relation between the 
strength of the acid, the temperature of the milk, and the 
color of the fat. 

First: — From a sample of milk measure the usual quantity for 
testing into each of three bottles, A, B and C. Place A in ice 
water, and C in warm water, leaving bottle B at the ordinary 
temperature. After the bottles have been left for twenty minutes 
under these conditions, add the normal quantity of acid to each 
and proceed with the test in the ordinary manner. 

Second: — Measure some of the same milk into three other bot- 
tles, D, E and F. Into test bottle D pour the usual amount of 
rather weak acid; add the same amount of acid of normal strength 
(1 .82-1.93) to bottle E. and add 17.5 cc. of a still stronger acid, 
(concentrated sulfuric acid, sp. gr. 1.84) in test bottle F; complete 
these tests in the usual way. 

On the completion of the preceding six tests the operator will 
notice that the fat in the necks of test bottles A (cold milk) and 
D (weak add) is much lighter colored than that in C {warm milk) 
and F {strong acid), and that the color of the fat in B {normal 
temperature) and E {normal acid) is somewhere between that of 
these two series. 

70. Influence of temperature on the separation of 
fat. The intensity of the action of the sulfuric acid on the 
milk is influenced by the temperature of either liquid; the 
higher the temperature, the more intense will be the action 
of the acid on the solids of the milk. It may be noticed 
that acid from the same carboy will act differently on milk 
in summer than in winter time, if the acid and the milk are 
not brought to the same temperature before testing during 



6o Testing Milk and Its Products, 

both seasons, by cooling or heating, respectively. The 
temperature of the liquids may be as low as 40° F. in winter 
and as high as 80° F. in summer. This difference of forty 
degrees will often have considerable influence on the clear- 
ness of the fat separated, showing white curdy substances, 
and a light colored fat in winter, and black flocculent specks, 
with a dark colored column of fat in summer. Both these 
defects can be avoided when the acid is of the proper 
strength, by bringing the temperature of the milk and the 
acid to about 70° F. before the milk is tested. 

The operator should be particularly cautious against over- 
heating either milk or acid; so intense an action may be 
caused thereby as to force the hot acid out of the neck of 
the test bottle when it is added to the milk, thus spoiling 
the test and possibly causing an accident. 

4. — Water to be Used in the Babcock Test. 

71, Rain water, condensed steam, or soft water should 
be used for the purpose of bringing the fat into the neck of 
the test bottles. The surface of the fat column will then 
usually be clear and distinct. The foam or bubbles that 
sometimes obscure the upper line (meniscus) of the fat, 
making the point indistinct from which to measure it, is gen- 
erally caused by the action of the acid on the carbonates in 
hard water. The carbonic acid gas liberated from hard 
water by the sulfuric acid is more or less held by the viscid 
fat and produces a layer of foam on its surface. If clean 
soft water cannot be obtained for this purpose, hard water 
may be used by adding a few drops of sulfuric acid to the 
water before it is heated, thus causing the carbonic acid to 
be driven out of it. By simply boiling, most hard waters 
will be rendered soft, and adapted to use in the Babcock 



The Babcock Test. 



6i 



test, as the carbonates which cause this foaming are thereby 
precipitated. 

If the test has been completed, and a layer of foam ap- 
pears over the fat, it may be removed by adding a drop or 
two of alcohol which will destroy the foam. If this is done, 
the fat column should be read as rapidly as possible after 
the alcohol is added, and before the latter unites with the 
fat and increases its volume. 




Fig. 21. The Russian test. 

72. Reservoir for water. When only a few tests are 
made at one time, the hot water can be added with the 17.6 
cc. pipette. If many tests are made, the water is more con- 



62 Testing- Milk and lis Products. 

veniently and quickly filled into the test bottles by drawing 
it from a small copper reservoir or tin pail suspended over 
the testing machine.* The flow of water through a rubber 
tube connected with the reservoir, is regulated by means of 
a pinch cock. The water must be hot when added to the 
test bottles so as to keep the fat in a melted condition until 
the readings are taken. 

The use of zinc or steel oilers, or perfection oil cans has 
been suggested, as a handy and rapid method of adding hot 
water to the test bottles. 

5. — Modifications of the Babcock Test. 

73. The Russian milk test. The same chemical and 
mechanical principles applied in the regular Babcock test, 
yy are used in the Russian milk test, ex- 
// cept that in this case the machine in 
// which the bottles are whirled, and 

// the bottles themselves, are so con- 

tf^ // structed that the latter can be filled with hot 
water while the machine is running at full 
speed, thus saving time and trouble incident to 
the stopping of the tester and filling the bottles 
by means of a pipette. The milk-measuring 
pipette (fig. 22) and the acid measure used in the 
Russian test are one-half the ordinary size, and 
the test bottles are made in two pieces, with a 
detachable narrow graduated stem (see fig. 23). 
The machine is substantially made of cast iron; 
it is provided with a very satisfactory speed indi- 
cator which shows at any time the number of 
Fig. 22. Pip. revolutions at which the bottles are being turned. 

ette usedin the rrii • '^^ j. >• t_ ^u 

Russian test. ^^^ accompanying illustrations show the appa- 

* Ordinary tinware rusts very soon when water is left standing in it, and cop- 
per reservoirs are therefore more economical. 



The Babcock Test. 



63 



n 



ratus used in the Russian test. In our experience with this 
machine there seemed to be a tendency toward too low 
results. 

74. Bartlett's modification. Bartlett* proposed a 
modification of the method of procedure in the Babcock 
test, which aims to simplif}^ the manipu- 
lations. 20 cc. of acid are added, instead 
of 17.5 cc, and the bottles filled with 
the milk-acid mixture are left standing 
for not less than five minutes and then 
filled to within the scale, with hot water; 
the bottles are then whirled for five 
minutes at the regular rate (48). 

In the experience of the authors the 
modification cannot always be depended 
upon to give satisfactory results. It 
was tried by each of the one hundred 
students in the Wisconsin Dairy School 
during 1896-'97; while some of these operators obtained a 
clear separation of fat, and results that compared favorably 
with those made by the regular Babcock test, others failed 
to obtain correct results with the method as modified. It 
is not known that the modification has proved superior to, 
or taken the place of the regular Babcock test to any extent, 

* Maine experiment station, bull. No. 31, (S. S.) 






Fig. 23. Test bottles 
used in the Russian test. 



64 



Testing Milk and Its Products. 



CHAPTER IV. 

CREAM TESTING. 

75. Cream may be tested by the Babcock test in the 
same manner as milk, and the results obtained are accurate 




Fig. 24. Students'testing dairy products 



^W=*^^^--=«^^ 



when the necessary care has been taken in sampling the 
cream and in measuring the fat. The composition of cream 
varies greatly according to the process of creaming, tem- 
perature of milk during the creaming, quality and composi- 
tion of the milk to be creamed, etc. The cream usually met 
with in the creameries or on the market will contain from 



Cream Testing. 65 

15 to 30 per cent, of fat; during late years the practice in 
man}^ creameries has been to churn a very rich cream, 
<3ontaining from 30 to 40 per cent, of fat. Such cream is, 
however, rarely met with, and cream containing 25 per cent, 
of fat may be considered of average composition for a good 
quality of cream. ^ If 18 grams of such cream is measured 
into an ordinary Babcock test bottle, it follows that there will 
be 18 X .25 = 4.5 grams (or 1^^^ = 5 cc.) of pure butter fat in the 
bottle. It is shown, however, (p. 34), that the space from 
to 10 in the neck of these bottles holds exactly 2 cc. The 
neck of the milk test bottles will not therefore be large 
enough to show the per cent, of fat in a sample of cream if 
18 grams are taken for testing, so that less cream must be 
measured out, or special forms of test bottles used (79). 

76. Errors of measuring cream. Several factors 
tend to render inaccurate the measuring of cream for the 
Babcock test, and in exact work, it is recommended to 
weigh the amount taken for a test. If a 17.6 cc. pipette is 
used for measuring the cream, it will not deliver 18 grams 
of cream, as it will of milk, for the following reasons: 

1. The specific gravitj^ of cream is lower than that of 
milk; if a certain quantity of milk weighs 1030 lbs., the same 
quantity of cream will weigh from 1020 lbs. to below 1000 
lbs., the weight being determined by the richness of the 
cream; the more fat the cream contains, the less a certain 
quantity of it, e. g., a gallon, will weigh. f 

2. Cream is thicker (more viscous) than milk at the same 
temperatures, and more of it will adhere to the sides of the 
measuring pipette than in case of milk. This is of special 
importance in testing very rich or sour cream. 

* For average quality of cream furnished at five Connecticut creameries 
see (194). 

t For specific quantity of cream of different richness, see table on p. 66. 
5 



C^ Testing Milk and Its Products* 

3. In case of separator cream, more or less air will become 
incorporated with the cream during the process of separa- 
tion. In the ripening of cream, fermentation gases are de- 
veloped and held in the cream in the same way as bread 
dough holds the gases generated by the yeast. In either 
case the weight of a certain measure of cream is diminished.. 

77. As an illustration of the effect of the preceding fac- 
tors on the amount of cream measured out by a Babcock 
17.6 cc. pipette, the following weighings of separator cream 
are given. The cream was in all cases fresh from the sep- 
arator; it was weighed as delivered by the pipette into a 
Winton cream bottle (81), and the test proceeded with at 
once. The specific gravity of the cream measured out was 
determined by means of a picnometer. The data given are 
in all cases averages of several determinations; the samples^ 
of cream have been grouped according to their average fat 
contents.* 

Weight of cream delivered hy a 17.6 cc. pipette. 

Per ct. of fat in cream Specific gravity (17.5° C.) Weight of cream delivered, grams 

10 1.023 17.9 

15 1.012 17.7 

20 1.008 17.3 

25 1.002 17.2 

30 .996 17.0 

35 .980 16.4 

40 .966 16.3 

45 .950 16.2 

50 .947 15.8 

The data given in the table show plainly the variations irt 
the specific gravity of cream of different richness and the 



* For influence of condition of cream on the amount measured out with a 17.6 
cc. pipette, see also Bartlett, Maine exp. sta., bull. 31 (s. s.) 



Cream Testing, 67 

error of making tests of cream by measuring it with a 17.6 
CO. pipette; if the cream to be sampled is fresh separator 
cream, testing over 30 per cent., less than 17.0 grams of 
cream will be delivered into the test bottle, and the results 
of the reading will be at least one- eighteenth too low, or 
about 1.4 per cent, on a 25 per cent, cream. If the cream 
is sour, the error will of course be still greater. 

78. Avoiding errors of measuring cream. The pre- 
ceding table shows that a 17.6 cc. pipette in case of cream 
containing less than 25 per cent, of fat, and fresh from the 
separator, will deliver only about 17.2 grams of cream; it 
is therefore evident that the pipette to deliver cream for the 
Babcock test must be made larger than the 17.6 cc. pipette 
used in testing milk. Quite satifactory results may be ob- 
tained in testing such cream, by using a 18 cc. measuring 
pipette; to avoid the expense and trouble of using two dif- 
ferent pipettes, one for milk and one for cream, a pipette 
with two marks on the stem, at 17.6 cc. and at 18 cc, has 
been placed on the market, the former mark being used when 
milk is tested, and the latter for cream. 

In testing cream by the Babcock test, one of two methods 
may be followed: 

First, one of the special forms of cream test bottles which 
have been devised is used; or, 

Second, only sufficient cream to be tested in a regular 
Babcock milk test bottle is taken for a sample. 

79. Cream test bottles. Three special forms of bot- 
tles have been devised for testing samples of cream by the 
Babcock test; two of these were suggested by Bartlett of 
Maine,* in 1892; one with a long detachable neck designed 



* Maine experiment station, bulletins 3 and 4 (second series). 



68 



Testing Milk and Its Products, 



m 



for testing very rich cream (up to 35 per 
cent, fat), and the other with a neck wid- 
ened into a bulb in the middle so as to 
allow a large quantity of fat to be meas- 
ured. The former kind of cream bottle 
has, so far as is known to the writers, found 
but a limited distribution; the neck is too 
long to be used in the ordinary centrifugal 
machines, and is not attached until the 
base portion, containing the cream, acid 
and first filling with water, has been 
whirled. This cream bottle is more difficult 
to handle and cannot be considered as 
practical as either of the two other forms 
of bottles devised for testing cream. 

80. The hulh-necked cream bottles, (fig. 
25), allow the testing of cream containing 
23 or 25 per cent, of fat, the usual quantity 
of cream (18 grams) being measured out. 
The neck is graduated from to 23 per 
cent., and in some cases to 25 per cent, the 
graduation extending both below and 
above the bulb. This is sometimes an in- 
convenience, as the water must be added 
carefully so that the lower end of the col- 
umn of fat will always come below the 
bulb, in the graduated part of the neck, and 
not in the bulb itself. Especially in case 
of beginners, tests are often lost when this 
bottle is first used, for the reason given, 
until the operator learns to add the proper amount of hot 



Fig. 25. The bulb- 
uecked cream test 
bottle. 



Cream Testing, 



69 




water to float the fat to some point within the scale. It is 
recommended to fill these bottles with the first portion of 
hot water to just above the bulb, so that 
one can see how much water to add the 
second time in order to bring the fat within 
the scale. 

Each division of the scale on these cream 
bottles represents two-tenths of one per 
cent, of fat, as in case of the milk test 
bottles. 

81. The Winton cream bottle. The cream 
test bottle devised by Winton,* (fig. 26), 
has a neck of the usual length, and suffi- 
ciently wide to measure 30 per cent, of fat. 
The scale of the neck is divided into one- 
half percents, but readings of a quarter 
of a percent can easily be estimated. De- 
terminations of fat in cream accurate to a 
quarter of a percent are sufficiently exact 
for most commercial purposes, e. g., in 
creameries, and this form of cream bottle 
will be found very convenient in making 
tests of composite samples of cream. 

82. Use of milk test bottle. Cream 
may be tested by emptying a 17.6 cc. pip- 
ettef ul of the sample into two or more test 
bottles, dividing the amount about equally 
between the bottles, and filling the pipette 
with water once or twice, which is then in 

turn divided about equally between the test bottles; the 

* Connecticut experiment station (New Haven), bull. No. 117- report 1894 
p. 224. 



Fig. 26. The Win 
ton cream bottle. 



*]0 Testing Milk and Its Products. 

per cent of fat in the cream is found by adding the 
readings obtained in each of the bottles. This method 
does away with the error incident to the adhesion of cream 
to the side of the pipette, but not that due to the low speci- 
fic gravity of the cream, and the results obtained will there- 
fore be somewhat too low. The dilution of the cream with 
water in the test bottles not only makes it possible to bring 
into the bottle all the cream measured out, but also insures 
a clear test. If ordinary cream is mixed with the usual 
quantity of sulfuric acid used in the Babcock test, a dark- 
colored fat will generally be obtained, while the cream 
diluted with an equal or twice its volume of water, when 
mixed with the ordinary amount of acid, will give a light 
yellow, clear column of fat, which will allow of a very dis- 
tinct and sharp reading. 

The number of bottles to be used for testing a sample of 
cream by this method must be regulated by the richness of 
the cream. If a sample probably contains 20 per cent, or 
more, one pipetteful should be divided nearly equally be- 
tween three milk test bottles, and two-thirds of a pipetteful 
of water is added to each bottle. If the cream contains 
less than 20 per cent, of fat, it will only be necessary to 
use two milk test bottles, dividing the pipetteful between 
these, and adding one-half of a pipetteful of water to each 
bottle. 

By using cream test bottles (79), more accurate tests may 
be obtained, in case of cream containing as much as 25 per 
cent, of fat, by dividing one pipetteful between two bottles, 
rinsing half a pipette of water into each one, than by add- 
ing all the cream to one bottle, without rinsing the pipette, 
for reasons apparent from what has been said in the pre- 
ceding. 



Cream Testing. 71 

83. Use of 5 cc. pipette. When the cream is in good 
condition for sampling, satisfactory results can be obtained 
by the use of a 5 cc. pipette; 5 cc. of cream are measured 
into a milk test bottle, and two pipettefuls of water are 
added. In this way all the cream in the pipette is easily 
rinsed into the test bottle. The readings multiplied by 
11 = 3.6 will give the per cent, of fat in the cream. If the 
specific gravity of the cream tested varies appreciably 
from 1, corrections should be made accordingly; e. g,. 
if the specific gravity is 1.02, the factor should read 



_1L_ = 3.63: 

6xl.0'2 



if .95, 



3.79, etc. 



84. Weighing the cream. For the reasons already 
given, it is always to be preferred to weigh the cream into 
the test bottles when accurate tests are required. When a 
small delicate balance is used, this can be done quite rap- 
idly. Either of the scales shown in the accompanying illus- 
tration (figs. 27 and 28), will be found useful and sufficiently 
accurate for this purpose; a small scale of this kind is also 





Fig. 27. Scale used for weighing 
cream, cheese, etc., in the Babcock 



Fig. 28. Torsion balance used 
for weighing cream, cheese, etc., la 
the Babcock test. 



convenient and helpful in testing cheese, butter and con- 
densed milk, and in determining the strength of sulfuric acid, 
and the accuracy of test bottles and pipettes (q. v.). In test- 
ing cream by weight, the test bottle is first weighed empty, 



72 Testing Milk and Its Products, 

and again when 5 to 10 cc. of cream have been measured into 
it; the difference between the two weights gives the weight 
of cream taken for the test. If the cream contains less than 
30 per cent, of fat, the regular milk test bottle can be used for 
testing the cream, if not much more than 5 grams are 
weighed out; if more cream is taken, or if this is richer 
than 30 per cent., it is advisable to use the bulb-necked 
cream bottle. 

The operator should be careful in weighing the cream 
not to spill it on the outside of the test bottle, as the bal- 
ance does not discriminate between cream inside and out- 
side of the bottle. Sufficient water is added to the bottle 
to make the total volume about 15 cc. The usual quantity 
of acid (17.5 cc.) is then added, and the test completed in 
the ordinary manner. The reading of the amount of fat in 
the neck of the test bottle in this case does not show the 
correct per cent, of fat in the cream, because less than 18 
grams were weighed out. The per cent, of fat in the cream 
tested is obtained by multiplying the reading by 18, and 
dividing the product by the weight of the cream taken. 

Example: Weight of cream tested, 5.2 grams; reading of col- 
umns of fat 1^4.8, 2)4,7^ average 4.75; per cent, of fat in the cream 

ilZ^XlS =16.44. 
5.2 

The weighing of cream and the reading of the fat column 

must be made very carefully; a division of one-tenth on the 

neck of the test bottle has a value of over three-tenths of 

one per cent, of fat when 5 grams of cream are tested, and 

six-tenths of one per cent, if only 3 grams of cream are 

weighed out. The reading is rendered more accurate and 

certain if a number of tests of a sample are made, at least 

two or three, and the results averaged. 



Cream Testing. 



n 



The accompanying illustration, (fig. 29), shows the proper 
method of reading the fat column in cream tests; readings 
are made from a to 5, not to d or to c. 

85. No special precautions other than those required in 
testing milk have been found necessary in testing cream, 
except that it is sometimes advisable not 
to whirl the test bottles in the centrifuge 
at once after mixing, but to let the cream- 
acid mixture stand for a while, until it 
— d turns dark colored. At first, the mixture 
of cream and acid is much lighter colored 
than that of milk and acid, owing to the 
smaller amount of solids not fat contained 
in the cream. 

The liquid beneath the fat in a completed 
test of cream is sometimes milky, and the 
fat appears white and cloudy, making an 
exact reading difficult. Such defects can 
usually be overcome by placing the test 
bottles in hot water for about 15 minutes 
previous to the whirling, or by allowing 
the fat"coiumrfln"he the fat to crystallizc (which is done by 

neck of a cream hot- i i i • • 

tie. Readings should cooliug the bottlcs in ICC water or cold water 

be made from a \o b, 

not to d or to c. after the last whirling) and remelting it by 

placing the bottles in hot water. 




74 Testing Milk and Its Products. 



CHAPTER V. 
BABCOCK TEST FOR OTHER MILK PRODUCTS. 

86. Skim milk, butter milk, and whey. Each di- 
vision on the scale of the neck of the regular Babcock 
test bottle represents two-tenths of one per cent. (39). When 
a, sample of skim milk or butter milk containing less than 
this per cent, of fat, is tested, the estimated amount is ex- 
pressed by diflerent operators as one-tenth, a trace, one- 
tenth trace, or one to five hundreths of one per cent. Gravi- 
metric chemical analyses of skim milk have shown that 
samples which give only a few small drops of fat floating 
on the water in the neck of the test bottle, or adhering to 
the side of the neck, generally contain one-tenth of one 
per cent, of fat, and often more. Samples of skim milk 
containing less than one-tenth of a per cent, of fat are very 
rare, and it is doubtful whether a sample of separator skim 
milk representing a full run of, say 5000 lbs. of milk has 
ever shown less than five -hundreths of one per cent, of fat. 
Under ordinary factory conditions, few separators will 
deliver skim milk containing under one-tenth of one 
per cent, of fat, when the sample is taken from a whole 
day's run. This must be considered a most satisfactory 
separation.* 

87. The reason why the Babcock test fails to show all 
the fat present in skim milk must be sought in one or two 



" For comparative analyses of separator skim milk by the gravimetric method 
and by the Babcock test, see bull. 52, Wis. exp. station. 



Babcock Test for Other Milk Products, 75 

causes: a trace of fat may be dissolved in the sulfuric acid, 
or owing to the minuteness of the fat globules of such 
milk they may not be brought together in the neck of the 
bottles at the speed used with Babcock test. If a drop of 
the dark liquid obtained in a Babcock bottle from a test of 
whole milk, be placed on a slide under the microscope, it 
will be seen that a fair number of very minute fat globules 
are found in the liquid. These globules are not brought 
into the column of fat in the neck of the bottle by the cen- 
trifugal force exerted in the Babcock test; the loss of the 
fat contained in these fine globules is compensated for, in 
the testing of whole milk, by a liberal reading of 
the column of fat separated out, the reading being 
taken from the lower meniscus of the fat to the top of 
the upper one (see p. 32); in some separator skim milk, on 
the other hand, not enough fat remains to completely fill 
the neck, and the apparent result of the reading must there- 
fore be increased by from five-hundredths to one-tenth of 
one per cent. 

It follows from what has been said that tests of skim milk 
showing no fat in the neck of the test bottles on completion 
of the test, generally indicate inefficient work of the centri- 
fugal tester, or the operator, or both. The test should be 
repeated in such cases, using more acid and whirling for full 
four minutes. 

In order to bring as much fat as possible into the neck of 
the bottles, in testing skim milk, it is advisable to add some- 
what more acid than when whole milk is tested, viz: about 
20 cc, and to whirl the bottles at full speed for four to five 
minutes. The readings must be taken as soon as the whirl- 
ing is completed, as owing to the contraction of the liquid 
by cooling, the fat is otherwise spread over the inside of 



76 



Testing Milk and Its Products. 



the neck of the test bottle as a film of grease which cannot 
be measured by the scale. 

88. The double-necked test bottle, (fig. 30), suggested by 
one of us,* is made especially for measuring small quanti- 
ties of fat and gives most satisfactory re- 
sults in testing skim milk and butter milk. 
Each division of the scale in these bottles 
represents five-hundredths of one per cent., 
and the marks are so far apart that the small 
fat column can be easily estimated to single 
hundredths of one per cent. In the first 
forms, now not in common use, the neck was 
graduated to hundredths of one per cent. 

The value of the divisions of the scale on 
the double-necked test bottles has been dis- 
cussed of late in dairy papers, and various 
opinions have been expressed whether they 
show one-tenth or one-twentieth (.05) of one 
per cent, of fat. By calibration with mercury 
the value of the divisions will be found to be 
.05 or one-twentieth of one per cent., but, as 
shown above, the results obtained in using 



Fig. 30. The 
double-necked 
skim milk bot- 
tle, (sometimes 
called the Ohls- 
son or B. & W. 
bottle). 



the bottles for thin separator skim milk come 
.05 to .1 per cent, too low, so that, practically 
speaking, each division may be taken to show 
one-tenth of one per cent., if the column of 
fat obtained fills only one or two divisions of the scale. 

The double-necked bottle is very convenient for the 
testing of separator skim milk, thin butter milk and 
whey. The milk, acid, and water are added to the bottle 



* Farrington, and constructed by Mr. J. J. Nussbaumer, of Illinois. 



Babcock Test for Other Milk Products. 77 

through the large side-tube; the mixing of milk and acid, 
and the addition of hot water, must be done with great care 
so that none of the contents are forced into the fine measur- 
ing tube and lost. When the fat is in the lower end of the 
measuring tube, it can be forced up into the scale by press- 
ing tightly with the finger on the top of the side tube. 

This test bottle is more fragile and expensive than the 
ordinary Babcock bottles, and unless carefull}^ handled, 
will not prove a good investment; the bottle has recently 
been made of heavier glass and this form is to be highly 
recommended. 

89. The double-sized skim milk bottle is of no particular 
value. It is difficult to obtain a thorough mixture of the 
milk and the acid in these bottles, and the tests invariably 
€ome too low, more so than in case of the regular Babcock 
bottles, or the double-necked skim milk bottles. 

90. The testing of butter milk or whey by the Babcock 
test offers no special difficulties, and what has been said in 
regard to tests of separator skim milk is equally true in 
case of these by-products. Whey contains only a small 
quantit}^ of solids not fat (less than 7 per cent), and the 
mixing with acid, and the solution of the whey solids therein, 
is therefore readily accomplished; the acid solution is of a 
light reddish color, turning black but very slowly. 

91. Cheese. Cheese can be easily tested by the Bab- 
cock test if a small scale (fig. 27-8) is at hand for weighing 
the sample; the results obtained will furnish accurate 
information as to the amount of fat in the cheese, provided 
good judgment and exactness is used in sampling and 
weighing. The following method of sampling the cheese is 
recommended: * 



* U. S. Dept. of Agriculture, Chemical Division, bull. No. 46, p. 37. 



^8 Testing Milk and Its Products. 

" Where the cheese can be cut, a narrow wedge reaching 
from the edge to the center of the cheese will more nearly 
represent the average composition of the cheese than any 
other sample. This may be cut quite fine, with care to 
avoid evaporation of water, and the portion for analysis 
taken from the mixed mass. When the sample is taken 
with a cheese trier, a plug taken perpendicular to the sur- 
face, one-third of the distance from the edge to the center 
of the cheese, should more nearly represent the average 
composition than any other. The plug should either reach 
entirely through or only half through the cheese. 

" For inspection purposes the rind may be rejected, but for 
investigations, where the absolute quantity of fat in the 
cheese is required, the rind should be included in the sam- 
ple. It is well, when admissible, to take two or three plugs 
on different sides of the cheese and after splitting them 
lengthwise with a sharp knife, take portions of each for the 
test." 

92. When a satisfactory sample of the cheese has been 
obtained, about 5 grams are weighed into a milk test bottle, 
or a larger quantity may be used with a cream test bottle. 
The test bottle is first weighed empty, and again after the 
pieces of cheese have been added. About 15 cc. of hot 
water is added to the cheese in the test bottle, and this is 
shaken occasionally until the cheese softens and forms a 
creamy emulsion with the water. A few drops of strong 
ammonia will aid in this mixing and disintegration, the pro- 
cess being hastened by placing the test bottles in hot water. 
When all lumps of cheese have disappeared in the liquid, 
the test bottles are cooled to about 70° F., acid is added, 
and the test completed in the ordinary manner. 



Babcock Test for Other Milk Products. 79 

The per cent, of fat m the cheese is obtained by multiply- 
ing the reading of the fat column by 18 and dividing the 
product by the weight of cheese added to the test bottle. 
The weighing of the cheese and the reading of the fat must 
be done with great care, since any error introduced is more 
than trebled in calculating the per cent, of fat in the cheese, 

93. Condensed milk. The per cent, of fat in con- 
densed milk can be obtained by weighing about 8 grams 
into a test bottle and proceeding in exactly the same way as 
given under testing of cheese. It is not necessary to add 
ammonia or to warm the condensed milk in the test bottles, 
since the solution of this in water is readily effected with- 
out any outside agency. Enough water should be added 
to make the total volume of liquid in the bottles about 17.6 
cc. 

If a scale is not available for weighing the sample, fairly 
accurate results may be obtained by diluting the condensed 
milk with water (1:1), and completing the test in the ordi- 
nary manner. When this is done, the results must be cor- 
rected for the dilution which the sample received. 



So Testing Milk and Its Products, 



CHAPTER YI. 
THE LACTOMETER AND ITS APPLICATION. 

94. The Quevenne lactometer. This instrument, (see 
fig. 31), consists of a hollow glass cylinder weighted down by 
means of mercury or fine shot so as to fioat in milk in an 
upright position, and provided with a narrow stem at its 
upper end, inside of which is found a graduated paper scale. 
In the better forms, like the Quevenne lactometer shown in 
the figure, a thermometer is melted into the cylinder, with 
its bulb at the lower end of the lactometer, and its stem 
rising above the lactometer scale. 

The lactometer is used for the determination of the spe- 
cific gravity of milk. The term specific gravity, means the 
weight of a certain volume of a solid or a liquid substance 
compared with the weight of the same volume of water at 
4° C (39.2° Fahr.); for gases the standard of comparison is 
air or hydrogen. If the milk which a can will hold, weighs 
exactly 103.2 lbs., this can will hold a smaller weight of 
water, say, 100 lbs., as milk is heavier than water; the spe- 
cific gravity of this milk will then be 1^ = 1.032. 

95. The lactometer enables us to determine rapidly the 
relative weight of milk and water. Its application rests on 
well-known laws of physics: When a body floats in a liquid, 
the weight of the amount of liquid which it replaces, is 
equal to the weight of the body. It will sink further into 
a light liquid than into a heavy one, because a larger vol- 



The Lactometer and Its A-ppltcation. 




Fig. 31. Quevenne 
lactometer floating in 
milk in a tin cylinder 
<100). 

6 



ume of the former will be required to 
equal the weight of the bod}'. A lac- 
tometer will therefore sink deeper into 
milk of a low specific gravity than into 
milk of a high specific gravity. 

The scale of the Quevenne lactome- 
ter is marked at 15 and 40, and divided 
into 25 equal parts, with figures at each 
five divisions of the scale. The single 
divisions are called degrees. The 15 de- 
gree mark is placed at the point to which 
the lactometer will sink when lowered 
into a liquid of a specific gravity of 1.015, 
and the 40 degree mark, at the point to 
which it will sink when placed in a 
liquid of a specific gravity of 1.040. 
The specific gravity therefore is changed 
to lactometer degrees by multiplying by 
1000 and substracting 1000 from the 
product. 

Example: Given, specific gravity 1.0345; 
corresponding lactometer degree, 1.0345 
X 1000 — 1000 = 34.5. 

96. Influence of temperature. 

Like most liquids, milk will expand on 
being warmed, and the same volume 
will therefoie weigh less when warmed 
than before; that is, its specific gravity 
will be decreased. It follows then that a 
lactometer is onl}' correct for the tem- 
perature at which it is standardized. If 



82 Testing Milk and Its Products. 

a lactometer sinks to the 32 mark in a sample of milk of a 
temperature of 60" F., it will sink below this mark if the 
temperature of the milk is 50° F., and will not sink so far 
down as 32, if the temperature is 70° F. Lactometers in the 
market at present are generally standardized at 60° F., and 
to show the correct specific gravity, the milk to be tested 
should first be warmed (or cooled, as the case may be) 
to exactly 60° F. As this is a somewhat slow process, tables 
have been constructed for correcting the results for errors 
due to differences in temperature (see Appendix). 

97. As the fat content of a sample of milk has a marked 
influence on its specific gravity at different temperatures, the 
coefficient of expansion of fat differing greatly from that of 
the milk serum, the table cannot give absolutely accurate 
corrections for all kinds of milk, whether rich or poor. But 
the errors introduced by the use of one table for any kind 
of whole milk within a comparatively small range of tem- 
perature, like ten degrees above or below 60°, are too small 
to have any importance outside of exact scientific work, and 
in such, the specific gravity is always determined by means 
of a picnometer, or a specific gravity bottle, at the tempera- 
ture at which the calibration has been made. In taking the 
specific gravity of a sample of milk by means of a lacto- 
meter, the milk is always warmed or cooled so that its tem- 
perature does not vary ten degrees either way from 60° F. 

98. The temperature correction table for whole milk^ 
given in the Appendix shows that if, e. g., the specific grav- 
ity of a sample of milk taken at 68° F. was found to be 
1.034, its specific gravity would be 1.0352 if the milk was 
cooled down to 60°. If the specific gravity given was found 
at a temperature of 50°, the correct specific gravity of the 
milk would be 1.033. 



The Lactometer and Its Afph'cation. 83 

In practical work in factories or at the farm, sufficiently 
accurate temperature. corrections may generally be made by 
adding .1 to the lactometer reading for each degree above 
60° F., and by subtracting .1 for each degree below 60°; e. g.^ 
if the reading at 64° is 29.5, it will be about 29.5 f .4 = 
29.9 at 60° F.; and 34.0 at 52° F. will be about 84.0 — .8 
= 33.2 at 60° F. By reference to the table in the AppendiXy 
we find it to be 33.0 in either case. 

The scale of the thermometer in the lactometer should be 
placed ahove the lactometer scale so that the temperature 
may be read without taking the lactometer out of the milk; 
this will give more correct results, will facilitate the reading 
and save time. 

99. N. Y. Board of Health lactometer. In the East, 
and among city milk inspectors generally, the so-called New 
York Board of Health lactometer is often used. This doe& 
not give the specific gravity of the milk directly, as is the 
case with the Quevenne lactometer, but the scale is divided 
into 120 equal parts, known as Board of Health degrees, the 
mark 100 being placed at the point to which the lactometer 
sinks when lowered into milk of a Specific gravity of 1.029 
(at 60° F.); this is considered the lowest limit for specific grav- 
ity of normal cow's milk. The zero-mark on the scale shows 
the point to which the lactometer will sink in water; the 
distance between these two marks is divided into 100 equal 
parts, and the scale is continued below the 100 mark to 120. 
As 100° on the Board of Health lactometer corresponds to 
29° on the Quevenne lactometer, the zero mark showing in 
either case a specific gravity of 1, the degrees on the former 
lactometer may easily be changed into Quevenne lactometer 
degrees by multiplying by .29. To further aid in this 



84 



Testing Milk and Its Products. 



transposition, a table is given in the Appendix, showing the 
readings of the two scales, between 60° and ]20° on the 
Board of Health lactometer. 

100. Reading the lactometer. For determining the 
specific gravity of milk in factories or private dairies, tin 
cylinders, 1^ inches in diameter, and 10 inches high, with a 
base about 4 inches in diameter, are recommended, (see fig. 
31); another form of specific gravity cylinders, in use in 
chemical laboratories, is shown in fig. 32. The cylinder is 
filled with milk of a temperature ranging between 
50° and 70° F. to within an inch of the top, and 
the lactometer is slowly lowered therein until it 
floats; it is left in the milk for about half a minute 
before the lactometer- and the thermometer read- 
ings are taken, both to allow the escape of air which 
has been mixed with the milk in pouring it pre- 
paratory to the specific gravity determination, and 
to allow the thermometer to adjust itself to the 
temperature of the milk. The lactometer should 
not be left in the milk much more than a minute 
before the reading is taken, as cream will very soon 
Fig. 32. )3e2in to rise on the milk, and the reading, if taken 

Specific ^ 

gravity later, will be too high, as the bulb of the lactometer 
cylinder. ^.|^ ^^ floating in partially skimmed milk. In read- 
ing the lactometer degree, the mark on the scale plainly visi- 
ble through the upper portion of the surface meniscus of the 
milk should be noted. Owing to surface tension the milk 
in immediate contact with the lactometer stem will'^rise 
above the level of the surface in the cylinder, and this must 
be taken into consideration in reading the degrees. There 
is no need of reading closer than one-half of a lactometer 
degree in the practical work of a factory or dairy. 



The Lactometer and Its Af plication, 85 

101. Time of taking lactometer readings. The 

specific gravity of milk should not be determined until six 
to twelve hours after the milk has been drawn from the 
udder, as too low results are otherwise obtained.* The 
cause of this phenomenon is not definitely understood; it 
may lay in the escape of the gases in the milk, or in changes 
in the mechanical condition of the nitrogenous components 
of the milk, (most likely of the casein), occurring on stand- 
ing. The results obtained after twelve hours will as a rule 
come about one degree higher than when the milk is cooled 
down directly after milking, and its specific gravity then 
determined. 

Calculation of Milk Solids. 

102. A number of chemists have prepared formulas for 
the calculation of milk solids when the fat content and the 
specific gravity (lactometer reading) of the milk are known. 
By careful work with milk tester and lactometer it is 
possible by means of these formulas to determine the com- 
position of samples of milk with considerable accuracy out- 
side of, as well as in, chemical laboratories. As the com- 
plete formulas given by various chemists (Behrend and 
Morgen, Clausnitzer and Mayer, Fleischmann, Hehner and 
Richmond, Richmond, Babcock,)t are very involved, and 
require rather lengthy calculations, tables facilitating the 
figuring have been prepared. The formulas in use at the 
present time, in this country or abroad, are those proposed 
by Fleischmann, Hehner and Richmond, and Babcock. 
Babcock's formula forms the foundation of the tables for 
solids not fat given in the Appendix, as it is generally taught 
in American dairy schools. 

* Bulletin No. 43, Chem. Div., U. S. Dept. of Agriculture, p. 191. 
t Agricultural Science, vol. Ill, p. 139. 



86 Testing Milk and Its Products, 

By the use of these tables the percent of solids not fat 
corresponding to lactometer readings from 26 to 36, and to 
fat contents from 2 to 6 percent may be found. The for- 
mula, as amended in 1895, is as follows,* S being specific 
gravit}^, and / the percent of fat in the milk. 

vSolids not fat = / 100 S - Sf , _ \ ^ 00 - f ) 2.5 
VlOO — 1.0753 Sf / ^ 

103. The derivation of this formula is as explained in 
the following: 

Milk is considered a mechanical mixture of butter fat and milk 
serum, the latter being an aqueous solution (or in part semi- 
solution) of all the solid components of the milk, except the fat. 
If/ therefore designate the percent, of fat in a sample of milk, then 
1 00 — f = per cent, serum in the milk. 

Let furthermore the specific gravity of the serum be called x, 
and the increase in specific gravity of the milk caused by one per 
ceat. of serum solids = a. The difference between the specific 
gravity of milk serum and that of water is nearly directly pro- 
portional to the amount of serum solids present, and the per cent, 
of serum solids will therefore be obtained if this difference be divided 
by the constant factor a, representing the increase in specific 
gravity caused by one per cent, serum solids. If this per cent, be 
multiplied by the per cent, of serum in the milk, and the product 
divided by 100, the result will give the per cent, solids not fat in 
the milk, viz. : 

Per cent, solids not fat = X ... . (I) 

a 100 ^ ^ 

To find the value of x in terms of 5, the specific gravity, and /, 
the fat of the milk, it is necessary to determine the value of a from 
a large number of analyses. 

The volume of a substance in cc. is equal to its weight in grams 
divided by its specific gravity ; therefore 

Volume in cc. of 100 grams of milk = 



* Wisconsin experiment station, twelfth report, p. 120. 



The Lactometer and Its Amplication. 87 

Voli.ime in cc. of serum in 100 grams of milk = 

X 

The specific gravity of pure butter fat being ,93, therefore 
Volume in cc. of fat in 100 grams of milk = = 1.0753 f 

.c/o 

Since milk is made up of fat and serum, we have 
100 ^ 100 -f ^ 1.0^53 f 
S X 

By solving this equation we find that 

x= lOQS-sf .... (II) 

100 — 1.0753 Sf 
To obtain the value a, the last equation is solved for a large 
number of analyses of different kinds of milk. 1 is subtracted 
from the average value obtained for x (equation II) and the differ- 
ence is divided by the per cent, of serum solids. Such calculations 
have shown that the value of a with normal cow's milk will come 
very near .004; substituting therefore this value and that of x 
(equation II) in equation I, and reducing, we have 

Solids not fat= / lOQS-Sf _ \ ^^^^ _ ^ ^.s 

V 100 — 1.0753 Sf / 

101. The tables made up from this formula, giving the 
percentages of solids not fat corresponding to certain per- 
cents of fat and lactometer readings, are given in the Ap- 
pendix. A careful examination of the same discloses the 
fact that the percent of solids not fat increases uniformly 
at the rate of .25 percent for each lactometer degree, and 
.02 percent for each percent of fat. This relation is ex- 
pressed by the following simple formulas: ^' ">^ 
Solids not fat = i L X .2 f ' '^^ t '^\ 
Total solids = :^ L x 1.2 f , 
L being the lactometer reading at 60° F. (specific gravity 
X 1000 — 1000), and/ the percent of fat in the milk. 

Rule : a, To find the percent of solids not fat in milk, add 
two-tenths of the percent of fat to one-fourth of the lactometer 
reading, and 



88 Testing Milk and Its Products. 

b, To find percent of total solids in milk, add one and two- 
tenths times the percent of fat to one-fourth of the lactometer 
reading. 

These formulas and rules are easily remembered, and can 
be quickly applied without the use of tables. The results 
obtained by using them do not differ more than .04 percent 
from those of the complete formula for milks containing up 
to 6 percent of fat, and may be safely relied upon in prac- 
tical work. 

Adulteration of Milk. 

105. The problem of determining whether or not a sam- 
ple of milk is adulterated, becomes an important one in the 
work of milk inspectors, and dairy and food chemists. 
Managers of creameries and cheese factories are also some- 
times interested in ascertaining possible adulterations in 
case of some patron's milk, although at present, since the 
general introduction of the Babcock test in factories, and 
the payment for the milk on basis of the amount of butter 
fat delivered, the temptation to water or skim the milk has 
been largely removed. In the city milk trade, especially 
in our larger cities, watered or skimmed milk is still fre- 
quently met with, in spite of the vigilance of their milk 
inspectors or the officers of the city boards of health. 

When the origin of a suspected sample of milk is known, 
a second sample should always be taken on the premises by, 
or in the presence of, the inspector, and the composition of 
the two samples compared. If the suspected sample is con- 
siderably lower in fat content, than the second, so-called 
control-sample, with a normal percent of solids not fat, it i& 
skimmed; if the solids not fat are below normal, it is watered; 
and if both these percentages are abnormally low, the sam- 
ple is most likely both watered and skimmed. 



The Lactometer and Its Amplication. 89 

106. In order to determine whether or not a sample ot 
milk is skimmed, or watered, or both skimmed and watered, 
the percents of fat and of solids not fat in the sample must 
be ascertained, and if a control-sample can be secured, these 
determinations for both samples compared. The proper 
latitude to be allowed for the natural variation in the com- 
position of milk differs accordinoj to the origin of the milk; 
in case of milk from single cows, the variations in fat con- 
tent from day to day may exceed one percent, although 
under ordinary conditions the percent of fat in most cows' 
milk will not vary that much. The content of solids not 
fat is more constant, and rarely exceeds one-half of a per- 
cent from day to day with single cows. Cows in heat or 
sick cows may give milk differing considerably in composi- 
tion from normal milk.* 

107. Mixed herd milk is of comparatively uniform com- 
position on consecutive days, and as most milk offered for 
sale or delivered to factories is of this kind, the task of the 
milk inspector is made considerably easier and more certain 
on this account. Daily variations in herd milk beyond one 
percent of fat, and one-half percent of solids not fat, are sus- 
picious and may be taken as fairly conclusive evidence of 
adulteration. This is especially true in case the control- 
sample shows a comparatively low content of fat or solids 
not fat. 

108. Where a control-sample cannot be taken, the legal 
standards for fat or solids in milk, in force in the various 
states, are used as a basis for calculating the extent of 
adulteration of a sample of milk. A list of legal standards 
for milk in this country and abroad is given in the Appendix. 
These standards determine the limits below which the milk 



* Blyth, Foods, their Composition and Analysis, London, 1882, p. 246 et seq. 



po Testing Milk and lis Products. 

offered for sale must not fall within the respective states. 
Legally it matters not whether a sample of milk offered for 
sale has been skimmed or watered by the dealer or by the 
cow; in the latter case, the cows producing the milk are of a 
breed or strain that has been bred persistently for quantity of 
milk, without regard to its quality. In most states the legal 
standards for the fat content of milk is 3 per cent., and for 
solids not fat, 9 or 9.5 per cent. There are, however, cows 
that normally will produce milk containing only 2.5 to 2.8 
per cent, of fat and less than 8.5 per cent, solids not fat. 
Such milk cannot therefore be legally sold in most states in 
the Union, and the farmer offering such milk for sale, even 
if he does not know the composition of the milk produced 
by his cows, is as liable to prosecution as if he had directly 
watered the milk. By mixing the milk of several cows, the 
chances are that the mixed milk will contain more fat and 
solids not fat, than called for by the legal standard; if such 
should not be the case, cows producing richer milk must be 
added to the herd so as to raise the quality of the herd milk 
up to the legal standard. 

109. Calculation of extent of adulteration.* In the 

following formulas, the percents found in the control- 
samples, if such are at hand, are always substituted for the 
legal standards. 

a. Shimming. — 1. If a sample of milk has been skimmed, 
the following formula will give the number of pounds of fat 
abstracted from 100 lbs. of milk: 

Fat abstracted = (x) = legal standard for fat — f, . (I) 
/ being the percent of fat in the suspected sample. 

2. The following formula will give the percent of fat ab- 

* Woll, Handbook for Farmers and Dairymen, New York, 1897, pp. 207-8. 



The Lactometer and Its Afflication. 91 

stracted, calculated on the total quantity of fat, originally 
found in the milk: 

x=100-, , !^^}^l, ,, .... (II) 

legal standard for fat 

b. Watering. — 1. If a sample is watered, the calculations 
are most conveniently based on the percentage of solids not 
fat in the milk. 

Percent, of foreign ('' extraneous ") water in adulterated 

milk=100— , , , ^ P-^ -^. . . . (Ill) 

leg. stand, for solids not fat 

S being the percent, of solids not fat in the suspected sample. 

Example: — A sample of milk contains 7.5 percent, solids not 

fat; if the legal standard for solids not fat is 9 percent., 100 — 

7 5 X 100 

— — 1-^ = 16.7, shows the percent, of extraneous water in the 

milk. 

2. Watering of milk may also be expressed in per cent. 
of water added to the original milk, by formula IV: 

Percent, water added to original milk 
_ . s _ 100 X leg. stand, for sol. not fat ^^^ .yYN 

100 X 9 
In the example given above, — ^^— - — — 100 = 12 percent, of 

7.5 

water was added to the original milk. 

c. Watering and shimming. — If a sample has been both 
watered and skimmed, the extent of watering is ascertained 
by means of formula (III) or (IV), and the fat abstracted 
found according to the following formula: 

Percent, fat abstracted = 
(x)=leg. stand, for f ^t _ l£ii^^?5ii|li£L^^ii^' Xf .(V) 



92 



Testing Milk and Its Products. 



'Example : — A sample of milk contains 2.4 per cent, of fat, and 
8.1 per cent, solids not fat; then 



Extraneous water in milk = 100 — 



8.1 X 100 



10 per cent. 



Fat abstracted = 3 



9 X 2.4 



8.1 



= .33 per cent. 



100 lbs. of the milk contained 10 lbs. of extraneous water 
and .33 lbs. of fat had been skimmed from it.* 

110. other methods of adulteration. Milk which 
has been watered, or skimmed, or both, is sometimes further 
adulterated by unscrupulous milk peddlers through the 
addition of a small quantity of cheese color; this will mix 
thoroughly with the milk, and, if added judiciously, will im- 
part a rich cream color to it. The presence of foreign col- 
oring matter in milk is easily shown by shaking 10 cc. of 
the milk with an equal quantity of ether; on standing, a 
clear ether solution will rise to the surface; the solution 
will be yellow colored, if artificial coloring matter has been 
added to the milk, the intensity of the color indicating the 
quantity added; natural fresh milk will give a colorless 
ether solution. 



*The following blank will be found convenient for work in the 
laboratory or testing room : 



REPORT BY. 



DAIRY SCHOOL. 

DATE 189. 

MILK TEST. 



No. of 
sample. 



Lactome- 
ter read- 
ing. 



Tempera- ^Zltt^^ 
ture reading 

^^^^- at 60° 



Per cent, 
of fat. 



Solids not 
fat. 



Adultera- 
tion, kind 
and amt. 



Remarks. 



The Lactometer and Its Application. 93 

111, The following method given by Wallace"^ is claimed 
to detect one part of coloring matter in 100,000 of milk. 

About 30 cc. of milk are coagulated with a few drops of acetic 
acid by the aid of heat. The coloring matter of annatto being 
insoluble in acids, is precipitated with the casein. The coagulated 
mass is separated from the whey by straining through a coarse 
cotton cloth, and the excess of liquid pressed out. The casein is 
placed in a mortar and rubbed with ether. The ether is then 
poured into a separatory funnel and about 10 cc. of a dilute soda 
solution (1 : 100) are added. After thorough shaking, the funnel 
is set aside to allow the liquids to separate. The lower la^-er 
which consists of soda solution in which the annatto is dissolved 
is drawn off into a porcellain dish, and in it are placed two discs 
of filter-paper, and the liquid is greatly evaporated. If annatto 
is present, the discs will be dyed orange to buff color. One of the 
well-washed discs is moistened with a dilute sodium carbonate 
solution to fix the color; the other is touched with a drop of stan- 
nous chlorid, and becomes instantly changed in color to a rich 
pink. "This test may be used in any condition of the milk, and 
with as small a quantity as 10 cc." 

It is not known that other methods of adulterating milk 
than those mentioned are practiced at the present time. 

For methods of detection of preservatives in milk, see 
Chapter X. 



N. J. Dairy Commissioner Report, 1896, p. 



94 Testing Milk and Its Products. 



CHAPTER N\\. 
TESTING THE ACIDITY OF MILK AND CREAM. 

112. Cause of acidity in milk. Very soon after milk 
is drawn from the udder, it will be found to have an acid 
reaction, when phenolphtaleiu is used as an indicator.^ The 
acidity in fresh milk is not due to the presence of free or- 
ganic acids in the milk, like lactic or citric acid, but to acid 
phosphates, and possibly also in part to free carbonic acid 
gas in the milk, and to the acid reaction of casein. Even 
in case of so-called sweet milk, nearly fresh from the cow, 
a certain amount of acidity, viz: on the average .07 per- 
cent, is therefore found. When the milk is received at the 
factory it will rarely test less than .10 percent, of acid, 
calculated as lactic acid; some patrons bring milk day after 
day that does not test over .15 percent, of acid; others 
bring milk that tests from .20 to .25 percent, and some 
lots, although very rarely, will test as high as .3 of one per- 
cent, of acid. It has been found that milk will not usually 
smell or taste sour, or "turned," until it contains .3 to .35 
percent, of acid. 

113. The acidity in excess of that found normally in 
milk as drawn from the udder, is due to other causes than 
those described, viz: the presence of acid milk-components. 
Bacteriological examinations of milk from various sources 

* Freshly drawn milk shows an amphoteric reation to litmus, i. e., it colors blue 
litmus paper red, and red litmus paper blue. 



Testing the Acidity of Afilk and Cream. 95 

and of different age have shown that there is a direct rela- 
tion between the bacteria found in normal milk, and its 
acidity; the larger the number of bacteria per unit of milky 
the higher the acidity of the milk. The increase in the 
acidity of milk on standing is caused by the breaking-down 
of milk sugar into lactic acid through the influence of acid- 
forming bacteria. Since the bacteria get into the milk 
through lack of cleanliness during the milking, and careless 
handling of the milk after the milking, this being kept 
under conditions that favor the multiplication of the bac- 
teria contained thereiu, it follows that an acidity test of 
fresh milk give a very accurate measure of the care bestowed 
in handling the milk; such a test will show which patrons 
take good care of their milk and those who do not wash 
their cans clean, or their hands and the udders of the cows 
before milking, and have dirty ways generally in milking 
and caring for the milk. The acidity test will always be 
high in case of milk kept for more than a day (Monday 
milk) or delivered after a warm sultry day or night. The 
bacteria have had a chance to multiply enormously in such 
milk, even if it be kept cooled down to 40°-50° F., and as a 
result considerable quantities of lactic acid have been 
formed. The determination of the acidity of fresh milk is 
explained in detail below (128). 

114. Methods of testing acidity. Methods of meas- 
uring the acidity or alkalinity of liquids by means of certain 
chemicals giving characteristic color reactions in the pres- 
ence of acid or alkaline solutions (so-called volumetric meth- 
ods of analysis) have been in use for many years in chemical 
laboratories. They were applied to milk as early as 1872 
by Soxhlet,* and the method worked out by Soxhlet and 



* Jour. f. prakt. Chemie, 1872, p. 6, 19. 



96 Testing Milk and Its Products. 

Henkel has since been in general use by European chemists. 
They measured out 50 cc. of milk to which was added 2 cc. 
of a 2 percent alcoholic solution of phenolphtalein, and this 
was titrated with a one-fourth normal soda solution ^ (see 
below). In this country, Dr. A. Gr. Manns,t in 1890, pub- 
lished the results of work done in the line of testing the 
acidity of milk and cream, and the method of procedure and 
apparatus proposed by him has become known under the 
name of Manns test, and has been advertised as such by 
dealers in dairy supplies. 

115. Manns' test. The acid in milk or cream is 
measured by using an alkali solution of a strength, together 
with an indicator, which shows by a change of color in the 
milk when all its acid has been neutralized. Any of the 
alkalies, soda, potash, ammonia, lime or barium can be used 
for making the standard solution, but it requires the skill, 
and apparatus of a chemist to prepare it of the proper 
strength. A one-tenth normal solution % of caustic soda is 
the alkali solution used most frequently in determining the 
acidity of milk, and is the solution labeled Neutralizer of 
Manns' test. 



* Fleischmann, Lehrb. d. Milchwirtschaft, p. 23. 

t Illinois experiment station, bulletin No. 9. 

X A normal solution of a chemical is known by the chemist as a solution contain- 
ing as many grams of the chemical in a liter (1000 cc.) as the figure representing 
its molecular weight. Caustic soda is made up of an atom each of sodium (Na), 
oxygen (O), and hydrogen (H); its molecular weight is therefore 

23 + 16 + 1 = 40 
Na H 
A normal soda solution then is made by dissolving 40 grams of soda in water, 
making up the volume to 1000 cc; a one-tenth normal solution will contain one- 
tenth of this amount of soda, or 4 gr. dissolved in one liter. One cubic centimeter 
of the latter solution will contain .004 grams of soda, and will neutralize .009 grams 
of lactic acid. The formula for lactic acid is CsHgOs (see p. 16) and its molecu- 
lar weight therefore 3 X 12 + 6 X 1 + 3 X 16 = 90. A one-tenth normal solution 
therefore contains 9 grams per liter, and .009 grams per cubic centimeter. 



Testing the Acidity of Milk and Cream. 97 

The indicator used for this purpose is phenolpJitalein^ a 
yellowish light powder; its compounds with alkalies are 
red, in weak alkaline solutions, pink colored; while its acid 
compounds are colorless. The phenolphtalein solution used 
is prepared by dissolving 10 grams in 300 cc. of 90 percent, 
alcohol (Mohr). 

116. In testing the acidity of either milk or cream it is 
necessary to measure out with exactness the quantity of 
liquid to be tested; Manns recommended using a 50 cc. 
pipette. This amount of milk or cream is measured into a 
<;lean tin, porcellain or glass cup, a few drops of the phenol- 
phtalein solution are added, and the "Neutralizer" (or alkali 
solution) is cautiously dropped in from a burette, the point 
at which the solution stands before it is drawn out being 
noted. By constant stirring during this operation it will be 
noticed that the pink color formed by the addition of even a 
drop of alkali solution will at first entirely disappear, but 
as more and more of the acid in the sample becomes neu- 
tralized, the color will disappear more slowly, until finally a 
point is reached when the pink color remains permanent for 
a time. No more alkali should be added after the first ap- 
pearance of a permanent and uniform pink color in the 
sample. This color will fade and gradually disappear again 
on standing, owing to the efi'ect of the carbonic acid of the 
air, to which acid, phenolphlalein is very sensitive. The 
amount of the alkali solution used for the test is then ob- 
tained from the reading on the scale of the burette, and 
this shows the degree of acidity in the sample. The per 
cent, of acid in the sample is calculated by multiplying by 
.009 the number of cc. of alkali solution used, and dividing 
the product by the number of cc. of the sample tested, the 
quotient being multiplied by 100. 



98 Testing Milk and Its Products. 

c. c. alkali x .009 

Percent acidity = -. — - — 7—5 X 100 

•^ c. c. sample tested 

If 50 cc. of cream required 32 cc. of alkali solution to 

produce a permanent pink color, the percent of acid in the 

32 X 009 
cream would be ^- — X 100 =.58 percent. A part of 

this calculation may be saved by using a factor for multi- 
plying the number of cc. of alkali added in each test. This 
factor is obtained by dividing ,009 (the number of grams of 
lactic acid neutralized by one cc. of alkali solution) by the 
number of cc. of sample tested, and multiplying the quotient 
by 100. If a 50 cc. pipette is used for measuring the sample 
to be tested, the factor will be (.009 -^ 50) X 100 = .018; if a 
25 cc. pipette is used, the factor will be (.009 -f- 25) x 100 
= .036; and if a 20 cc. pipette is used, (.009 -^ 20) X 100 
= .045 will be the factor to be applied in calculating the 
percent of acidity, the number of cc. of alkali used being in 
all cases multiplied by the particular factor corresponding 
to the volume of the sample tested. 

117. A table showing the percent of acid corresponding 
to different quantities of alkali solution for a given quantity 
of milk or cream can be easily prepared by the use of the 
factors given, and the necessity of calculating the result in 
percent thus saved. If a 50 cc. pipette is used for measur^ 
ing out milk or cream, the table will thus be as follows: 



cc. alkali 


Corresponding 


CC. alkali 


Corresponding 


olution used 


acidity 


solution used 


acidity 


1 CC 


.018 percent. 


6cc 


.108 per cent 


2cc 


.036 


7cc 


.126 


3cc 


.054 


8cc 


.144 


4 cc 


.072 


9 cc 


.162 


5 cc 


.090 


10 cc 


.180 



Testing the Acidity of Milk and Creajn. 99 



With a little practice the operator will easily be able to 
determine the acidity of different portions of the same milk 
or cream to within 1 cc. of alkali solution (= .02 per cent, 
of acid, when a 50 cc. sample is taken). 

118. Manns s testing outfit. The 
apparatus (see fig. 33) and chemicals 
needed for testing the acidity of milk 
or cream by the so-called Manns' test 
include 1 gal. one-tenth normal alkali 
solution; 4 oz. of an alcoholic solu- 
tion of phenolphtalein, one 50 cc. 
glass burette with stop-cock, one bur- 
ette stand, and a pipette for measur- 
ing out the sample. This outfit will 
make about 100 tests and is sold for 
$5.00.* 

119. The alkaline tablet test. 

Solid alkaline tablets were proposed 
by Farrington in 1894, as a substitute 
for the liquid used in Manns' test.f 
It was found possible to mix a solid 
alkali and coloring matter, and com- 
press the mixture into a small tablet, 
which would contain an exact amount 
of alkali. The advantage of the tab- 
lets lies in the fact that they will keep 

. J J 11 1- ^^^- ^^' Apparatus used in 

tar better than a standard alkali Manns' test. 




* Devarda^i acidimeter (Milchzeiting, 1896, p. 785) is built on the same principle 
as Manns' test; one-tenth soda solution is added to 100 cc. of milk in a glass-stop- 
pered graduated flask, 2 cc. of a 4 per cent, phenolphtalein solution being used as 
an indicator. The graduations on the neck of the flask give the "degrees acidity" 
directly. 

t Illinois experiment station, bulletin No. 32. 



lOO Testing Milk and Its Products. 

solution, and they can be easily and safely sent by mail; 
they also require less apparatus and are considerably 
cheaper than standard alkali solutions; 1000 of these tab- 
lets, costing $2.00, will make about 400 tests * Similar alka- 
line tablets were placed on the market in Europe at about 
the same time, viz: Stokes' Acidity Pellets in 1893, and 
Eichler's Sceurepillen (acid-pills) in 1895.t 

Two methods of using the tablets have been proposed, 
one, for the titration (determination of acidity) of ripening 
cream, in the manufacture of sour-cream butter; and the 
other, for determining the approximate acidity of different 
lots of apparently sweet milk or cream. 

120. Determination of acidity in sour cream. 

The method is equally applicable for the determination of 
the acidity of sour cream, sour milk and butter milk, but is 
most frequently employed in testing the acidity of ripening 
cream, to examine whether or not the ripening process has 
reached the proper stage for churning the cream. The ap- 
paratus used (see fig. 34) are as follows: 

1 Babcock 17.6 cc. pipette. 

100 cc. graduated cylinders; it is well to provide two or 
three of these, although only one is strictly necessary. 

1 white cup. 

121. Preparation of the solution. The tablet solution 
used during the past two years was prepared by dissolving 
five tablets in 50 cc. of water; with 20 cc. of cream each 
cubic centimeter of this solution represents .017 percent of 
acidity (lactic acid) in the sample tested. The amount of 
acid in a given sample was then obtained by multiplying 



* The tablets are sold by dealers in dairy supplies, 
t Milchzeiting, 1895, pp. 513-16. 



Testing the Acidity of Milk and Creaju. loi 



the number of cubic centimeters of the tablet solution used 
by .017. 

122. According to a suggestion recently made* the 
strength of the solution has been changed in such a manner 
that the percentages of acidity are indicated directly by the 
number of cubic centimeter of tablet solution used in each 
test. The solution may be made up in two ways, viz: by 
use of a 20 cc. or a 17.6 cc. pipette. 





i 

Fig. 34. Apparatus used for determining the acidity of cream or millc. 

a. Use of 20 cc. ^pipette. When a 20 cc. pipette is used for 
measuring the sample to be tested, the tablet solution is 
prepared by dissolving one tablet for every 17 cc. of water; 
for five tablets 85 cc. of water are therefore taken. When 
made in this way, each cubic centimeter of solution repre- 



* By Mr. C. L. Fitcb, of Hoard's Creameries, (Hoard's Dairyman, Sept. 3, 1897). 



I02 Testing Milk and Its Products. 

sents .01 percent of acid in the sample tested, 20 cc. of cream 
being taken; the number of cubic centimeters required 
to produce a pink color in the sample tested as read off 
directly from the graduations of the cylinder used for mak- 
ing the tablet solution gives the percent of acid in the sam- 
ple, 10 cc. being equal to .10 percent acid, 32 cc. to .32 per- 
cent, 65 cc. to .65 percent, etc. 

b. Use of 17.6 cc. pipette. The 17.6 cc. milk pipette of the 
Babcock test may be used for measuring the sample for 
acidity testing, and the results read directly from the grad- 
uated cylinder, if the tablet solution is prepared by taking 
one tablet for every 19.5 cc. of water; five tablets are there- 
fore dissolved in 97 cc. of water. 

123. As cream during its ripening process should gen- 
erally have from .5 to .6 percent of acid, before it is ready 
to churn, a 50 cc. cylinderful of tablet solution of this 
strength will not be sufficient to make a test of cream con- 
taining over .5 percent of acid, although it is enough for 
testing the cream up to this point during the ripening pro- 
cess. The acid-testing outfit should therefore contain a 100 
cc. graduated cylinder, instead of one of 50 cc. capacity, so 
that cream of any amount of acidity up to one percent can 
be tested. A tablet solution of the strength given has not 
only the advantage over the solution previously recom- 
mended* (5 tablets to 50 cc. of water) of showing the per- 
cent of acidity directly, without tables or calculations, but 
being weaker, the unavoidable errors of determination are 
decreased by its use. 

Equally accurate results may be obtained by using solu- 
tions made up according to method a or method 5, explained 

* 111. exp. sta., bull. 32 ; Wis. exp. sta., bull. 52. 



Testing the Acidity of Milk and Cream. 103 

in the preceding. Thie latter method (17.6 cc. cream, 5 
tablets per 97 cc. of water) has, however, the advantage in 
point of economy of apparatus, since a 17.6 cc. pipette is 
found in creameries and dairies with the Babcock test out- 
fit and is therefore most likely already available for use in 
testing the acidity of cream. This method is therefore con- 
sidered preferable and referred to as 

124. The standard solution. The preparation of this 
solution is as follows: Five tablets are added to the 100 cc. 
cylinder which is filled to the 07 cc. mark with clean soft 
water, tightly corked, shaken and laid on its side, as the 
tablets will dissolve more quickly when the cylinder is 
placed in this position than when left in an upright position 
with the tablets at the bottom. Several cylinders con- 
taining the tablet solution may be prepared; as soon as 
one is emptied, tablets and water are again added, 
and the cylinder is corked and placed in a horizontal posi- 
tion. In this way fresh solutions ready for testing are 
always at hand. The cylinder is kept tightly corked, while 
the tablets are dissolving, so that none of the liquid is lost 
by the shaking. It is well to put the tablets in the cylinder 
with water at night; the solution will then be ready for use 
in the morning. Excepting a flocculent residue of inert 
matter, " settlings," which will not dissolve, the tablets must 
all disappear in the solution before this is used. The 
strength of the tablet solution does not change perceptibly 
by standing for twenty-four hours; but a change takes place 
in solutions more than a day old. The solid tablets will not 
change if kept dry. The only precaution necessary is to 
use a fresh solution when acidity tests are made. 

125. Making the test. The cream to be tested is thor- 
oughly mixed, and 17.6 cc. is measured into the cup. The 



I04 Testing Milk and Its Products. 

pipette is rinsed once with water, and the rinsings added to 
the cream in the cup. A few cc. of the tablet solution pre- 
pared as given above are now poured from the cylinder into 
the cream, and mixed thoroughly with it by giving the cup 
a gentle rotary motion. The tablet solution is added in small 
quantities until a permanent pink color appears in the sam- 
ple. The number of cc. of tablet solution which have been 
used to color the cream is now found from the scale of the 
cylinder. 

In comparing the results of one test with another, 
the same shade of color should always be adopted. The 
most delicate point is the first change to a uniform pink 
color which the sample shows when the acid contained there- 
in has just been neutralized. This shade of color is easily 
recognized with a little practice. The pink color is not per- 
manent unless a large excess of alkaline solution has been 
added, on account of the influence of the carbonic acid of 
the air (116), and the operator should not therefore be 
lead to believe by the reappearance of the white color 
after a time, that the point of neutralization was not 
alread}^ reached when the first uniform shade of pink was 
observed. 

126. Acidity of cream. 17.6 cc. of sweet cream is gen- 
erally neutralized by 15-20 cc. of this tablet solution, rep- 
resenting from .15 to .20 percent, of acid. A mild sour 
cream is colored by 35 cc. tablet solution, and a sour cream 
ready for churning, by about 50 cc. tablet solution. As the 
cream ripens, its acidity increases. The rate of ripening 
depends largely on the temperature at which the cream is 
kept. Cream containing .5 to. 6 per cent, of acid will make 
such butter as our American market demands at the present 
time. Cream showing an acid test of .55 per cent, may not 



Testing the Acidity of Milk and Creafu. 105 



^z 



be too sour, but .65 per cent, of acid is very near, if not on 
the danger line, since such cream is likely to make strong 
flavored, almost rancid butter. Each lot of cream should be 
tested as soon as it is read}^ for ripening, and the result of 
the test will show whether the cream should be warmed or 
cooled in order to have it ready for churning at the time 
desired. Later tests will show the rate at which the ripen- 
ing is progressing, and the time when the cream has reached 
the proper acidity for churning. 

127. Spillman's cylinder. The graduated cylinder, 
shown in fig. 35, was devised by Prof. Spillman of Wash- 
ington experiment station, for use in testing 
the acidity of milk and cream with Farring- 
ton's alkaline tablets. The following direc- 
tions are given * for making tests with this 
piece of apparatus. 

" All that is needed in addition to the acid 
test graduate shown in the accompanying 
illustration is a common prescription bottle 
of six or eight ounce capacity, and a package 
of Farringtons alkaline tablets. Fill the 
bottle with water and add one tablet for each 
ounce of water in the bottle. Shake the bot- 
FiG 35 s iii-^ ^^^ frequently to aid in dissolving the tablets, 
man's cylinder, " Maldiig the test. In making the test, the 

used in determin- .,j, t../>iit^^i i 

ing the acidity of ^^^^ ^cst graduate IS filled to the zero mark 
cream or miiic. ^i^\^ the milk or crcam to be tested. The tab- 
let solution is then added, a little at a time, and the 
graduate shaken after each addition, in order to thoroughly 
mix the milk and the tablet solution. In shaking the 



* Wasliington experiment station, bulletin No. 24. 



io6 Testino Milk and Its Products. 



"ti 



graduate, give it a rotary motion to prevent spilling any of 
the liquid. Continue adding the tablet solution until a per- 
manent pink color can be detected in the milk. The level 
of the liquid in the graduate, measured by the scale on the 
graduate, will then be the percent, of acidity of the milk. 
It is best to stand the graduate on a piece of white paper, 
so that the first pink coloration of the milk may be easily 
detected." 

128. Rapid estimation of the acidity of appar= 
ently sweet milli or cream, a. Milk. The alkaline tab- 
let method offers a ready means of estimating the acidity 
of fresh milk or cream that is still apparently sweet. The 
selection of the best kinds of milk is especially important 
in pasteurizing milk or cream. Investigations have shown 
that milk which gives the highest acid test contains, as a 
rule, a larger number of bacteria and spores, not destroyed 
by pasteurization, than does milk giving a low acid test; the 
acidity test may therefore be used to advantage for the 
purpose of selecting milk best adapted for pasteurization, as 
well as such as is to be retailed or used in the manufacture 
of high-grade butter and cheese. 

In distinguishing milk fit for pasteurization purposes 
from that which is doubtful, an arbitrary standard of two- 
tenths of one percent of acid may be taken as the upper 
limit for milk of the former kind. The apparatus used in 
making this test is shown in the accompanying illustra- 
tion, (fig. 36), and consists of a white tea cup; either a four, 
six or eight ounce bottle, and a No. 10 brass cartridge shell, 
or a similar measure. A solution of the tablets in water is 
first prepared, one tablet being always added for each ounce 
of water: four tablets in a four ounce bottle; six, in a six 



Testing the Acidity of Milk mid Cremn. 107 



ounce bottle, etc., the amount of tablet solution prepared 
depending on the number of tests to be made at one time. 
The bottle is filled up to its neck with clean soft water, and 
the solution prepared in the manner previously given (124). 
The manner of operating the test is as follows: 






SOunceBoUle. "Measure 

Fig. 36. Apparatus used for rapid estimation of the acidity of apparently sweet 
milk or cream. 

129. Operating the test. As each lot of milk is brought 
to the creamery in the morning and poured into the weigh 
car, it is weighed, and the cartridge-shell dipper filled with 
the milk; this is then poured into the white cup. The same 
or another No. 10 shell is now filled twice with the tablet 
solution, and emptied into the milk in the cup. Instead of 
dipping twice with one measure or a No. 10 shell, a tin 
measure can be made holding as much as two No. 10 
shells. The liquids are then mixed in the cup by giving 
this a quick rotary motion. The color of the mixture is now 



io8 Testing Milk and Its Products. 

noticed. If the milk remains white it contains more than 
two-tenths of one percent of acid, and should not be used 
for pasteurization. If it is colored after having been thor- 
oughly mixed with two measures of tablet solution, it con- 
tains less than this amount of acid and may be safely used, 
as far as acidity goes, for pasteurization or any other pur- 
pose for which it is necessary to have thoroughly sweet 
milk. The shade of color obtained will vary with different 
lots of milk ; the sweetest milk will be most highly colored, 
but a milk retaining even a faint pink color with two 
measures of tablet solution to one measure of milk contains 
less than .2 percent acid. 

By proceeding in the manner described, the man at the 
factory weigh can is able to test the acidity of the milk de- 
livered nearly as quickly as he can weigh the milk; and ac- 
cording to the results of the test he will send the milk to 
the general delivery vat, or to the pasteurization vat, as the 
weighing can may be provided with two conductor spouts. 

130. Size of measure necessary. It is not necessary to 
use a No. 10 shell for a measure in working the preceding 
method; one of any convenient size that can be filled ac- 
curately and quickly, will answer the purpose equally well,. 
if a measure of the same size is used for- both the sample 
and the tablet solution. When this is done, each measure- 
ful of tablet solution made up as directed, will represent 
one-tenth percent of acid in the sample tested. 

131. b. Cream. Cream can be tested in the way already 
described for testing the acidity of fresh milk, by adding ta 
one measureful of cream in the cup, as many measures of 
tablet solution as are necessary to change the color of the 
cream when the two liquids are thoroughly mixed. If one 



Testing the Acidity of Milk and Creaijt. 109 

measure of tablet solution colors one measure of cream, this 
contains less than .1 percent acid; if five measures of tablet 
solution are required, the cream contains about .5 percent 
acid, etc. By proceeding in the manner described, the ope- 
rator can estimate the acidity to within .05 per cent, of 
acid, if half measures of tablet solution used are observed. 
The results thus obtained are sufficiently delicate for all 
practical purposes. 

132. Detecting preservaline * in milk. The tablet solution 
furnishes a simple method of detecting preservaline in milk. The 
application of the alkaline tablets for this purpose was first dis- 
cussed in bulletin No. 52 of Wisconsin experiment station. The 
acidity of the milk is increased by the addition of preservaline, but 
neither the odor nor taste of the milk is affected thereby. By ad- 
ding to sweet milk the amount of preservaline which the manu- 
facturers claim will keep it sweet for 36 hours, its acidity may be 
increased to .35 per cent., in a sample of milk which before adding 
the preservaline tested perhaps only .15 per cent. acid. 

As before stated, unadulterated milk will usually smell or taste 
sour, or "turned", when it contains .30-.35 per cent, acid; milk 
testing as high as this limit, which neither smells nor tastes sour 
in any way, is therefore in all probability adulterated with pre- 
servaline or some other preparation containing boracic acid, or a 
similar compound. 

133. "Alkaline Tabs." These are not alkaline tab- 
lets, but a substitute which was put on the market by a 
New York firm. The outfit furnished consisted of four 
packages of paper discs made of filter paper, each of about 
the size of an old-style copper cent; two packages of square 
paper; one glass of about 10 cc. capacity, and one small 



* Preservaline is the trade name of an antiseptic extensively advertized for 
preserving milk and cream. It consists essentially of boracic acid and borax, the 
use of which in milk and other dairy products oflfered for sale, is prohibited by 
law in many states. 



no Testing Milk and Its Products. 

glass bottle. The directions stated that each paper disc 
represented .1 per cent, acidity when added to the small 
glassful of milk or cream, with two of the square papers, 
the whole to be well shaken in the long glass bottle. The 
acidity of the sample of milk or cream was claimed to be 
measured by counting the number of round papers required 
to produce a pink color in the sample tested. 

An investigation of the reliability of these " Tabs " soon 
disclosed the fact that they were entirely inaccurate, and 
that no dependence could therefore be put on the results 
obtained by their use. A report of the comparative work 
done in testing the acidity of milk or cream by a one-tenth 
normal alkali solution and these " Alkaline Tabs " was pub- 
lished in the dairy press in 1895, to which reference is here 
made as to the details sf the results obtained.* 



Hoard's Dairyman, Sept. 6, 1895. 



Testing the Purity of Milk. 



Ill 




Fig. 37. Students operating the Wisconsin curd test. 



CHAPTER YIII. 
TESTING THE PURITY OF MILK. 

134. The Wisconsin curd test. Cheese makers are 
often troubled with so-called floating or gassy curds which 
produce cheese defective in flavor and texture. These faults 
are usuall}^ caused by some particular lot of milk containing 



112 Testing Milk and Its Products. 

impurities that cannot be detected by ordinary means of in- 
spection. The Wisconsin curd test is used to detect the 
^source of these defects and thus enable the clieese maker 
to exclude the milk from the particular farm or cow to 
which the trouble is traced. This test is similar in princi- 
ple to tests that have for many years past been in use in 
cheese-making districts in Europe, notably in Switzerland,* 
but was worked out independently at the Wisconsin Dairy 
School in 1895 and has become generally known as the Wis- 
consin curd test from the description of it in the report of 
Wis. experiment station for 1895.t The method of operat- 
ing this test is as follows (see fig. 37). 

135. Method of making the test. Pint glass jars, thor- 
oughly cleaned and sterilized with live steam, are provided; 
they are plainly numbered or tagged, one jar being pro- 
vided for each lot of milk to be tested. The jars are filled 
about two-thirds full with the milk from the various sources 
(it is not necessary to take any exact quantity); they are 
then placed in a tank or vat containing water, which is 
heated until the milk in the jars has a temperature of 98° F. 
The thermometer used must not be transferred from one 
sample to another, unless special precautions are taken, for 
fear of contaminating the pure lots of milk by impure ones. 

When the milk has reached a temperature of 98°, add to 
each sample, 10 drops of rennet extract, and mix by giving 
the jar a rotary motion. The milk is thus curdled, and the 
ourd allowed to stand for about twenty minutes until it is 
firm. It is then cut fine with a case knife, and after settling, 
the whey is poured oflf. The best tests are made when the 
separation of the whey is most complete. By allowing the 



* Herz, Unters. d. Kuhmilch, Berlin, 1889, p. 87. 
t Twelfth report, p. 148. 



Testing the Purity of Milk. 113 

samples to stand for a short time, more whey can be poured 
off, and the curd thereb}^ rendered firmer. The water around 
the jars is kept at a temperature of 98°, the vat is covered, 
and the curds allowed to ferment in the sample jars for six 
to twelve hours. 

During this time the impurities in any particular sample 
will cause gases to be developed in the curds so that by 
examining the same carefull}^, by smelling of them, and 
cutting them with a sharp knife, those having a bad flavor 
or a spong}' or in any way abnormal texture may be easil}^ 
detected, and the lot of milk from which it was made, 
thereby picked out. 

136. By proceeding in the same way with the milk from 
the different cows in a herd, the mixed milk of which pro- 
duced abnormal curds, the source of contamination in the 
herd may be located. Very often the trouble will be found 
to come from the cows' drinking foul stagnant water or from 
fermenting matter in the stable. In the former case the 
pond or marsh must be fenced off, or the cows kept away 
from it in other ways; in the latter, a thorough cleaning 
and disinfection of the premises are required. If the milk 
of a single cow is the source of contamination, it must be 
kept by itself, until the milk is again normal; under such 
conditions the milk from the healthy cows may of course 
safel}^ be sent to the factory. 

137. The fermentation test. The Gerber fermenta- 
tion test (see fig. 38) furnishes a convenient method for 
discovering the cause of abnormal fermentations which show 
themselves in tainted, pin-holey, gassy, or floating curds, 
and is also useful in examining the purity of different lots 
of milk. The test consists of a tin tank which can be heated 



114 Testing Milk and Its Products. 

by means of a small lamp, and into which a rack fits, hold- 
ing a certain number of cylindrical glass tubes; these are 
all numbered and provided with a mark and a tin cover. In 
making the test, the tubes are filled to the mark with milk, 
the number of each tube being recorded in a note book, 
opposite the name of the particular patron whose milk was 
placed therein. The tubes in the rack are put in the tank, 
which is two-thirds full of water; the temperature of the 




Fig. 



The Gerber fermentation test. 



water is kept at 104-106° F. for six hours, when the rack is 
taken out, the tubes gently shaken, and the appearance of 
the milk, its odor, taste, etc., carefully noted in each case. 

The tubes are then again heated in the tank at the same 
temperature as before, for another six hours, when observa- 
tions are once more taken of the appearance of the milk in 
each tube. The tainted milk may then easily be discovered, 
by the abnormal coagulation of the sample. 



Testing the Purity of Milk. 115 

According to Gerber,* good and properly handled milk 
should not coagulate in less than twelve hours, when kept 
under the conditions described, nor show anj^thing abnor- 
mal when coagulated. Milk from sick cows and from cows 
in heat, or with diseased udders will always coagulate in less 
than twelve hours. If the milk does not curdle inside of a 
day or two, it should be tested for preservatives (240). 

* Die praktische Milch-Pruefung; Woll, Handbook f. Farmers and Dairymen^ 
pp. 253-5. 



ii6 Test in or Milk and Its Products. 

c> 



CHAPTER IX. 
TESTING MILK ON THE FARM. 

139. Variations in milk of single cows. The varia- 
tions in the tests of milk of single cows from milking to 
milking, or from day to day, are greater than many cow- 
owners suspect. There seems to be no uniformity in this 
variation, except that the quality of the milk produced 
generally improves with the progress of the period of lacta- 
tion; even this may not be noticeable, however, except when 
the averages of a number of tests made at different stages 
■during the lactation period are compared with each other. 
When a cow gives her maximum quantity of milk, shortly 
after calving, the quality of her milk is generally poorer (by 
one percent of fat, or less) than when she is drjdng off". 
Strippers' milk is therefore as a rule richer in fat than the 
milk of fresh cows. 

140. By testing separately every milking of a number 
of cows through their whole periods of lactation, the results 
obtained have seemed to warrant the following conclusions 
in regard to the variations in the tests of the milk from 
single cows, and it is believed that these conclusions allow 
of generalization.* 

1. Some cows' milk tests about the same at every milking. 
Such cows generally give a uniform quantit}^ of milk from 
day to day. 



* Illinois experiment station, bulletin 24. 



Testing Milk on the Far^n. 117 

2. Other cows give milk that varies in an unexplainable 
way from one milking to another. Neither the morning nor 
the evening milking is alwa5's the richer, and even if the 
interval between the two milkings is exactly the same, the 
quality as well as the quantity of milk produced will vary 
considerably. Such cows are mostly of a nervous, excitable 
temperament, and are easily affected by changes in feed, 
drink, or surrounding conditions. 

3. The milk of a sick cow, or of a cow in heat, generally 
tests higher than when the cow is in a normal condition; 
the milk yield generally decreases under such condition; 
marked exceptions to this rule have, however, been observed. 

4. Starved or underfed cows may give milk testing higher 
than when the cows are properly nourished, probably on 
account of an accompanying feverish condition of the ani- 
mal. The milk is, however, more generally of an abnor- 
mally low fat content, which may be readily increased to 
the normal percent of fat in the milk by liberal feeding. 

5. Fat is the most variable constituent of milk, while the 
solids not fat vary within comparatively narrow limits. The 
summary of analysis of 2400 American samples of milk cal- 
culated by Cooke * shows that while the percentage of fat 
varies from 3.07 to 6.00 percent, or nearly three percent^ 
that of casein and albumen varies only from 2.92 to 4.30 
percent, or less than one and one-half percent, and the milk 
sugar and ash content increases but little (about .69 percent), 
as the milk grows richer, within the range given. 

6. A test of only one milking may give a very erroneous 
impression of the average quality of a certain cow's milk. 
A composite sample (see below) taken from two or more 

* WoU, Handbook for Farmers and Dairymen, p. 195. 



ii8 Testing Milk and Its Products. 

successive milkings will more nearl}^ represent the quality 
of the milk which a cow produces at the time of the samp- 
ling. 

141. The variations that may occur in testing the milk 
of single cows, are illustrated by the following figures ob- 
tained in an experiment made at the Illinois experi- 
ment station,* in which the milk of each of six cows was 
weighed and analyzed daily during the whole periods 
of lactation. Among the cows were pure-bred Jerseys, 
Shorthorns, and Holsteins, the cows being from 3 to 8 years 
of age, and varying in weight from 850 to 1350 lbs. During 
a period of two months of the year, the cows were fed a 
heavy grain ration consisting of 12 lbs. of corn and cob 
meal, 6 lbs. of wheat bran, and 6 lbs. of linseed meal, per day 
per head. This course of feeding was tried for the purpose 
of increasing, if possible, the richness of the milk. The 
influence of this heavy grain feed, as well as that of the first 
pasture grass feed, on the qualit}^ and the quantity of the 
milk produced is shown in the following table which gives 
the complete average data for one of the cows (No. 3). The 
records of the other cows are given in the publication re- 
ferred to; they were similar to the one here given, in so far 
as variations in quality are concerned. 



Bulletin No. 24. 



Testing Milk on the Farm. 



no 



Average results obtained in weighing and testing a cow's milk 
daily during one i^eriod of lactation. 





'53 
^ . 

la 

3 


Daily mi 
yield. 


Ik 


Tests of one day's 
milk. 


Yield of fat per 
day. 


Month. 


1. 

< 




^ CO 




1^ 


go 


bo 

2 




h 




920 
927 
1035 
1047 
1054 
1079 
1105 
1180 
1130 


12.1 
ItJ.O 
16.1 
14.3 
13.8 
14.5 
12.1 
9.3 
6.4 


16.0 
17.7 
17.7 
16.0 
16.5 
17.2 
14.0 
12.2 
9.3 


10.0 

14.0 

13.5 

12.5 

11.5 

10.0 

9.2 

6.0 

3.5 


3.8 
3.7 
3.6 
3.8 
4.0 
3.8 
3.9 
4.2 
4.7 


4.9 
4.6 
5.8 
4.7 
5.8 
4.6 
4.6 
6.2 
7.9 


3.0 
2.7 
3.2 
3.4 
3.0 
3.4 
3.2 
2.8 
2.9 


.46 
.59 
.58 
.54 
.55 
.55 
.47 
.39 
.30 


.60 
.76 
.84 
.61 
.72 
.70 
.57 
.60 
.50 


.34 


January 


.44 




.51 


Marc h 


.50 


April 


.46 


May 


.44 


June 


.35 


July 


.27 


August 


.16 







14-i. The average test of this cow's milk for her whole 
period of lactation was 3.8 per cent, of fat (i. e. the total 
quantity of fat produced -- total milk yield, X 100) ; the milk 
of the cow twice during this time tested as high as 5.8 per 
cent., and once as low as 2.7 per cent., while tests of 3.0 and 
4.6 per cent, were obtained a number of times. The aver- 
age weight of milk produced per day by the cow was 1-1 lbs. ; 
this multiplied by her average test, 3.8, shows that she pro- 
duced on the average .53 lbs., or about one-half a pound 
of butter fat per day during her lactation period. If, how- 
ever, her butter-producing capacity had been judged by the 
test of her milk for one day only, this test might have been 
made either on the day when her milk tested 5.8 per cent., 
or when it was as low as 2.7 per cent. Both of these tests 
were made in midwinter when the cow gave about 16 lbs. of 
milk a day. Multiplying this quantity by 5.8 gives .93 lbs. 
of fat, and by 2.7 gives .43 lbs.' of fat. Either result might 
show the butter fat produced by the cow on certain days, 
but neither gives a correct record of her actual average 
daily performance for this lactation period. 



I20 Testing Milk and lis Products. 

A sufficient number and variety of tests of the milk of 
many cows have been made to prove that there is no defi- 
nite regularity in the daily variations in the richness of the 
milk of single cows. The only change in the quality of milk 
common to all cows is, as stated, the natural increase in fat 
content as the cows are drying off, and even in this case the 
improvement in the quality of the milk sometimes does not 
occur until the milk yield has dwindled down very materially. 

143. Causes of variations in fat content. The quality 
of a cow's milk is as a rule decidedly influenced by the fol- 
lowing conditions: 

Rough treatment. 

Exposure to rain or rough weather. 

Change of feed. 

Change of milkers. 

Rapidity of milking. 

Length of interval between milkings. 

Unusual excitement or sickness. 

144. Disturbances like those enumerated frequently in- 
crease the richness of the milk for one, and sometimes for 
several milkings, but a decrease in quality follows during 
the reaction or the gradual return to normal conditions, and 
taken as a whole, there is a considerable falling oflf in the 
total production of milk and butter fat by the cow, on ac- 
count of the nervous excitement which she has gone through. 
Aside from changes due to well-definable causes, like those 
given above, the quality of some cow's milk will often 
change very considerably without any apparent cause. The 
dairyman who is in the habit of making tests of the milk of 
his individual cows at regular intervals, will have abundant 
material for study in the results obtained, and he will soon 



Testing Milk on the Farm. 121 

be able to tell from the tests made, if these are continued 
for several days, whether or not the cows are in a normal 
healthy condition, or have been subjected to excitement or 
abuse in any way. 

145. Number of tests required during a period of 
lactation in testing cows. The daily records of the six 
cows referred to on p. 118 give data for comparing their total 
production of milk and butter fat during one period of lac- 
tation, as found from the daily weights and tests of their 
milk, with the total amount calculated from weights and 
tests made at intervals of 7, 10, 15 or 30 days. The aver- 
ages of all results obtained with each of the six cows show 
that weighing and testing the milk of a cow every seventh 
day, gave 98 per cent, of the total milk and butter fat, 
which according to her daily record was the total product. 
Tests made once in two weeks gave 97.6 per cent, of the 
total milk, and 98.5 per cent, of the total butter fat, and 
tests made once a month, or only ten times during the period 
of lactation, gave 96.4 per cent, of the total milk, and 97 per 
cent, of the total production of butter fat. 

146. The record of one of the cows will show how these 
calculations are made: It was found from the daily weights 
and tests that cow No. 1, in one lactation period of 307 days, 
gave 5,04-1 lbs. of milk which contained 254 lbs. of butter 
fat. Selecting every thirtieth day of her record as testing 
day, the total production of milk and fat is shown to be as 
follows: 



122 



Testing Milk and Its Pi'oducts, 
Production of milk and butter fat per day. 



Testing day. 


Weight of milk. 


Test of milk. 




Yield of butter fat. 


Nov. 4 


lbs. 
20.5 
18.7 
17.7 
20.0 
18.2 
19.5 
17.7 
13.1 
12.2 

3.2 


per cent. 
4.7 
4.6 
4.9 
4.5 
4.7 
4.4 
4.8 
5.5 
6.2 
7.2 


lbs. 
.96 


Dec. 4 

Tan. 3 


.86 
.86 


Feb 2 


.90 


Mar. 3 


.86 


April 2 


.81 


May 2 

June 1 


.85 
.72 


July 1 

July 31 


.76 
.23 


Total, 


159.7 lbs. 
15.97 lbs. 




7.81 lbs. 


Average per day. 


4.89 


.78 lbs. 



The average daily production of the cow, according to the 
figures given in the preceding table, was nearly 16 lbs. of 
milk, containing .78 lbs. of butter fat. Multiplying these 
figures by 307, the number of days during which the cow 
was milked, gives 4903 lbs. of milk and 240 lbs. of fat. This 
is 141 lbs. of milk and 14 lbs. of fat less than the total 
weights of milk and butter fat, as found by the daily weights 
and tests, or 2.8 and 5.5 percent less, for milk and fat pro- 
duction, respectively. This is, however, calculated from 
only ten single weights and tests, while it required over 600 
weighings and 300 tests of the milk to obtain the exact 
amount, 

Similar calculations from the records of the other cows 
gave fully as close results, showing that quite satisfactory 
records of the total production of milk and butter of a cow 
may be obtained by making correct weighings and tests of 
her full day's milk once every thirty days. 



Testing Milk on the Farm. 123 

147. When to test a cow. The Vermont experiment 
station for several j^ears made a special stud}^ of the ques- 
tion when a cow should be tested in order to give a correct 
idea of the whole 3'ear's performance, when only one or two 
tests are to be made during the lactation period.* The results 
obtained may be brief!}- summarized as follows: 

a. As to quality of milk j^roduced. If two tests of each 
cow's milk are to be made during the same lactation period, 
it is recommended to take composite samples at the inter- 
vals given below. 

First sample. Second sample. 

For spring cows, 6 weeks after calving, 6V2-7V^ mos. after calving 
summer " 8 " " "16 -7 mos. " 

fall "8-10" " " 151/2-7 mos. 

If only one test is to be made, approximately correct re- 
sults may be obtained by testing the milk during the sixth 
month from calving, in case of spring cows; during the third 
to fifth month in case of summer calving cows, and during 
the fifth to seventh month for fall calving cows. 

In all cases composite samples of the milk for at least four 
da3'S should be taken (162). " The test of a single sample, 
drawn from a single milking or day, will not of necessity, or 
indeed, usually, give trustworthy results." 

This method of obtaining the average composition of the 
milk produced during a lactation period is naturally more 
correct in case of mixed herd milk, than when single cows 
are tested. 

b. As to quantity of milk produced. The milk may be 
weighed for four days in the middle of the month, and the 
entire month's yield obtained with considerable accuracy 
(barring sickness and drying off), by multiplying the sum by 



* Sixth report, 1892, p. 106; Ninth report, 1895, p. 1' 



124 



Testing Milk and Its Products. 



7, 7|- or 7f , according to the number of days in the different 

months. The weighing is most readily done by means of a 

spring balance, the 

hand of which is set 

back so that the 

empty pail brings it 

to zero (fig. 39). If 

several pails are to 

be used, they should 

first be made to 

weigh the same by 

putting a little 




■THE DAIRYMENi'S SUPPLY C0i4^ 
PHIL A. PA. ''^'^^^' 






Fig. 39. Milk scale. Fig. 40. Automatic milk scale for weighing and 

registering the milk of individual cows. 

solder on the lighter pails. Milk scales which weigh and 
automatically register the yield of milk from twenty cows 
have recently been placed on the market (see fig. 40); the 
pail is hung on the hook, and by pressing the button show- 
ing the number of the particular cow, the weight is recorded 
on the milk sheet. 



Testing Milk on the Farm. 125 

148. H. B. Gurler, the well-known Illinois dairyman, 
suggests* a method of determining the total production of 
a cow during one lactation period from the test of her milk 
for one week onl3\ This plan is, however, only recom- 
mended to those who cannot or do not care to take the neces- 
sary time to make a more reliable test. 

The test should be made after the cow has been in milk 
for about three months. It is necessary that the cow should 
be producing a normal quantity and qualit}'- of milk at the 
time when the the test is made; if, e. g., a cow is fresh March 
1, and tested June 1, she is probably on good pasture feed, 
and produces more milk and butter fat than at any previous 
or subsequent time. She should, therefore, be tested either 
before she is put on pasture or after the luxuriance of the 
pasture is gone, Mr. Gurler suggests that the milk be 
weighed for a week, and a composite sample taken of the 
milkings. At the end of this time it may be found that the 
cow gave 154 lbs. of milk during the week, and the com- 
posite sample tested 4.3 percent fat; the cow, therefore, pro- 
duced ^.^ lbs. of butter fat during the week, or on the 
average, .94 lbs. per day. This average yield is now multi- 
plied by 252, the number of days in 8.4 months, and a 
yield- of 237 lbs. of butter fat is obtained. This will very 
nearly represent the total production of fat by the cow 
during the whole period of lactation. 

It is assumed in this calculation that the cow gives milk 
more than 8.4 months, and that what is produced beyond 
this time will bring the production during the last 2.4 
months up to the same average per month as in the first six 
months. 



American Dairyiog.p. 18. 



126 



Test in o- Milk and Its Products, 



l-il). Record of tests. Where tests of the single cows 
in a herd are made regularly, a complete record should be 
kept in a note book arranged in about the manner shown on 
the following blank. 

RECORD OF TESTS OF COWS. 
MONTH , 189 



Date. 



Name of cow. 



Pounds 
of milk. 



! No. of 
1 test 
bottle. 



Percent. 

of 
butter fat 



Yield of 
butter fat 
pounds. 



Remarks. 



150. Sampling milk of single cows. In sampling 
the milk of single cows, all the milk obtained at the milking 
must be thoroughly mixed, b}^ pouring it from one vessel 
to another for a few times, or stirring it thoroughly by 
means of a dipper moved up and down, as well as horizon- 
tally in the pail or can in which it is held; the sample for 
testing purposes is then taken at once. A correct sample 
of a cow's milk cannot be obtained by milking directly into 
a small bottle from one teat, or by filling the bottle with a 
little milk from each teat, or by taking some of the first, 
middle, and last milk drawn from the udder. Such samples 
cannot possibly represent the quality of the milk of one 
entire milking, since there is almost as much diiference be- 
tween the first and the last portions of a milking, as between 
skim milk and cream.* Lack of care in taking a fair sample 
is the cause of many surprising results obtained in testing 
milk of single cows. 

151. When a cow is to be tested, she should be milked 
dry the last milking previous to the day when the test is to 



* Woll, Handbook for Farmers and Dairymen, p. 194; Agricultural Science, 
pp. 540-42. 



Testifig Milk on the Farm. 127 

be made. The entire quantity of milk obtained at each 
milking is mixed and sampled separatel3^ On account of 
the variations in the composition of the milk, a number of 
tests of successive milkings must be made. As this involves 
considerable labor, the plan of taking composite samples is 
preferable; the method of composite sampling and testing is 
explained in detail under the second subdivision of Chapter X 
(162) ; suffice it here to say that the method followed in case 
of single cows' or herd milk, is to take about an ounce of 
the thoroughly mixed milk of each milking; this is placed 
in a pint or quart fruit jar containing a small quantity of 
some preservative, preferably about one-half a gram of 
powdered potassium bi-chromate. If a number of composite 
samples of the milk of single cows are taken, each jar should 
be labeled with the number or name of the particular cows. 
Composite tests are generally taken for four days or for a 
week. If continued for a week, the jars will contain at the 
end of this time a mixture of the milk of fourteen milk- 
ings. The composite sample is then carefully mixed by 
pouring it gently a few times from one jar to another, and is 
tested in the ordinary manner. The result of this test shows 
the average quality of the milk produced by the cow during 
the time the milk was sampled, 

152. As the amount as well as the quality of the milk 
produced by single cows vary somewhat from day to day, 
and from milking to milking, it is quite important in testing 
single cows, especially when the test includes only a few 
days, to take a proportionate part (an aliquot) of each milk- 
ing for the composite test sample. This is easily done by 
means of a Scovell sampling tube, the use of which is ex- 
plained in another place (166). 



I2{ 



Testino Milk and Its Products. 



153. 5ize of the testing sample. Four ounces is a 
sufficient quantity for a sample of milk if it is desired to 
determine its percent of fat only; if the milk is to be tested 
with a lactometer, when adulteration is suspected, as much 
as a pint is needed for a sample. If this sample of milk is 
put into a bottle and carried or sent away from the farm to 
be tested, the bottle should be completely filled with milk, 
to prevent a partial churning of butter in the sample during 
transportation (25). 

154. Variations in herd milk. While considerable 
variations in the quality of milk of single cows are often 
met with, a mixture of the milk of several cows, or of a 
whole herd, is comparatively uniform from day to day; the 
individual differences tend to balance one another so that 
variations when they do occur, are less marked than in case 
of milk of single cows. There are, however, at times marked 
variations also in the test of herd milk on successive days; 
the following figures from the dairy tests conducted at the 
World's Columbian Exposition in Chicago in 1893 will show 
the correctness of this statement. The test included twenty- 
five cows each of the Jersey and the Guernsey breeds, and 
twenty-four of the Shorthorn breed. 

Tests of herd milk on successive days. 



Date. 


Jersey. 


Guernsey. 


Shorthorn. 


Tulv 16. 1893 


4.8 percent. 

5.0 

4.7 

4.6 

5.0 


4.6 percent. 

4.5 

4.4 

4.6 

4.5 


3.8 percent. 


Tulv 17 1893 


3.8 


July 18 1893 


3.8 


July 19, 1893 

July 20, 1893 


3.7 " 
3.8 







Testing Milk on the Farm. 129 

On July 17, 1893, the mixed milk of the Jersey cows 
tested two-tenths of one percent higher than on the preceding 
day; the Guernsey herd milk tested one-tenth of one per- 
cent lower, while the Shorthorn milk did not change in 
composition; comparing the tests on July 19 and 20, we find 
that the Jersey and Shorthorn milk tested four- tenths and 
one-tenth of one percent higher, respectively, on the latter 
day than on the former, and the Guernsey milk tested one- 
tenth of one percent lower. 

155. Ranges in variations of herd milk. According 
to Fleischmann,^ herd milk on single days may vary from 
the average values for the year, as follows, expressed in per- 
cent of the latter: 

The specific gravity (expressed in degrees) may go above 
or below the yearly average by more than 10 percent. 

The percent of fat content may go above or below the 
yearly average by more than 30 percent. 

The percent "of total solids ^may go above or below the 
yearly average by more than 14 percent. 

The percent of solids not fat may go above or below the 
yearly average by more than 10 percent. 

To illustrate, if the average test of a herd during a whole 
period of lactation is 4.0 percent, the test on a single day 
may exceed 4.0 + i^^o'o X 4.0 = 5.2, or may go below 2.8 per- 
cent, (viz. 4.0 — n)"o X 40); if the average specific gravity is 
1.031 (lactometer degrees 31),t the specific gravity of the 
milk on a single daj' may var}- between 1.0279 and 1.0341 
(31 + iJo"o X 31 = 34.1 ; 31 — iV'o X 3.1 = 27.9. 



* Book of the Dairy, p. 32. 
t See page 81, 
9 



130 Testing Milk and Its Products. 

156. Influence of heavy grain feeding on the quality 
of milk. If cows are not starved or underfed, an incrase 
in the feeding ration will not materially change the richness 
of the tnilk produced, as has been shown by careful feeding 
experiments, conducted under a great variety of conditions 
and in many countries. Cows that are fairly well fed will 
almost invariably give more milk when their rations are in- 
creased, but the milk will remain of about the same quality 
after the first few days are passed as before this time, pro- 
vided the cows are in good health and under normal condi- 
tions. Any change in the feed of cows will usually bring 
about an immediate change in the fat content of the milk, as 
a rule increasing it to some extent, but in a couple of days 
wh^n the cows have been accustomed to their new feed, the 
fat content of the milk will again return to its normal 
amount. 

157. The records of the cows included in the feeding 
experiment at the Illinois station, to which reference has 
been made on p. 118, furnish illustrations as to the effect of 
heavy feeding on the quality of milk. The feed as well as 
the milk of the cows were weighed each day of the experi- 
ment; during the month of December each cow was fed a 
daily ration consisting of 10 lbs. of timothy hay, 20 lbs. of 
corn silage and 2 lbs. of oil meal; the table on p. 119 shows 
that cow No. 3 produced on this feed, on the average, 12.1 
lbs. of milk, testing 3.8 percent of fat. In January the grain 
feed was gradually increased until the ration consisted of 12 
lbs. ot timothy hay, 8 lbs. of corn and cob meal, 4 lbs. of 
wheat bran, and 4 lbs. of oil meal. All cows gained in milk 
on this feed ; cow No. 3 thus gave an average of 4 lbs. more 
milk per daj^ in January than December, but the average 
test of her milk was 3.7 percent, or one-tenth of one percent 



Testing Milk on the Farm. 131 

lower than during the preceding month. The heavy grain 
feeding was continued through February and March, when 
it reached 12 lbs. of timothy hay, 12 lbs. of corn and cob 
meal, 6 lbs. of wheat bran and 6 lbs. of oil meal per day. 
The records show that the flow of milk kept up to 16 
lbs. per day in February, in case of this cow, but fell to 14 
lbs. in March and April, the average test of the milk being, 
in February, 3.6; in March 3.8, and in April, 4.0 percent. 
The milk was, therefore, somewhat richer in April than in 
December, but not more so than is found normally, owing to 
the progress of the period of lactation. 

158. Influence of pasture on the quality of milk. 
On May 1, the cows were given luxuriant pasture feed and 
no grain; a slight increase in the average amount of milk 
produced per day followed, with a reduction in the test, this 
being 3.8 percent, — the same as in December. 

During all these changes of feed, there was, therefore, not 
much change in the richness of the milk, while the flow of 
milk was increased by the heavy grain feeding for several 
months, as well as by the change from grain feeding in the 
barn to pasture feed with no grain.* 

159. The increase in the amount of butter produced by 
a cow, which has often been observed as a result of a change 
in feed, doubtless as a rule, comes from the fact that more, 
but not richer milk is produced. The quality of milk which 
a cow produces is as natural to her as is the color of her 
hair, and is not materially changed by any special system of 
normal feeding.f 



♦For further data on this point, see Cornell (N. Y.) exp. sta., bulletins 13, 22, 
36 and 49; N. D. exp. sta., bull. 16; Kansas exp. sta., report 1888; Hoard's Dairy- 
man, 1896, pp. 921-5. 

f On this point almost endless discussions have in recent years taken place in 
the agricultural press of this and foreign countries, and the subject has been under 



132 Testing Milk and Its Products. 

160. Method of improving the quality of rnXWu. The 

quality of the milk produced by a herd can generally be im- 
proved by selection and breeding, i. e., by disposing of the 
cows giving poor milk, say below 3 percent of fat, and by 
breediog to pure-bred or high-grade bulls of a strain that is 
known to produce rich milk. This method cannot work 
wonders in a day, or even in a year, but it is the only cer- 
tain way which we have to improve the quality of the milk 
produced by our cows. 

It may be well in this connection to call attention to the 
fact that the quality of the milk which a cow produces is 
only one side of the question; the quantity is another, and 
equally important one. Much dissatisfaction and grumbling 
about low tests among patrons of creameries and cheese 
factories would be stopped if this fact was more generally 
borne in mind. A cow giving 3 percent milk should not 
be condemned because her milk does not test 5 percent; she 
may give twice as much milk per day as a 5 percent cow, 
and will therefore produce considerabl}^ more butter fat. 



debate at nearly every gathering of farmers where feeding problems have been con- 
sidered. Many farmers are firm in their belief that butter fat can be •' fed into" 
the milk of a cow, and would take exception to the conclusion drawn in the pre- 
ceding. The results of careful investigations by our best dairy authorities point 
conclusively, however, in the direction stated, and the evidence on this point is 
overwhelmingly against the opinion that the fat content of the milk can be mate- 
rially and for any length of time increased by changes in the system of feeding. 
The most conclusive evidence in this line is perhaps the Danish co-operative cow 
feeding experiments, conducted during the p'sst ten years, with over 2,000 cows in 
all. The conclusion arrived at by the director of the Copenhagen experiment sta- 
tion, und ,'r whose supe-'vision and direction the experiments have been conducted 
has been stated over and over again in the published reports of the station: that 
the changes of feed made in thediffdrent lots of cows included in the experiments 
have had practically no influenc j on the chemical composition (the fat content) of 
the milk produced. In these experiments grain feeds have been fed against roots, 
against oil cake, and against wheat bran or shorts; grain and oil cakes have further- 
more been fed against roots, and roots have been given as an additional feed to the 
standard rations tried, — in all cases with tl\e same negative results as far aa 
changes iu the fat contents of the milk produced are concerned. 



Testing Milk on the Farm. 133 

The point whether or not a cow is a persistent milker is also 
of primary importance; a production of 300 lbs. of butter 
fat during a whole period of lactation is a rather high dairy 
standard, but one reached by many herds, even as the aver- 
age for all mature cows in the herd. Dairymen should re- 
member that a high production of butter fat in the course 
of the whole period of lactation is of more importance than 
a very high test. 



134 Testing Milk and Its Products. 



CHAPTER X. 
COMPOSITE SAMPLES OF MILK. 

161. Shortly after milk testing bad been introduced to 
some extent in creameries and cheese factories, it was sug- 
gested by Patrick, then of Iowa experiment station,* that a 
great saving in labor, without a coincident diminution in the 
accuracy of the results, could be obtained by mixing the 
daily samples of milk from one source, and testing this mix- 
ture, instead of each sample contributing thereto. Such a 
mixture is called a composite sample. The usual methods of 
taking such samples at creameries and cheese factories dur- 
ing the past few years have been as follows: 

162. Methods of taking composite samples, a. Use 

of tin dipper. Either pint or quart Mason fruit jars, or milk 
bottles provided with a cover, are used for receiving the 
daily samples. One of these jars is supplied for each patron 
of the factory and is labeled with his name or number. A 
small quantity of preservative (bichromate of potash, 
bichlorid of mercury, etc., (see 172) is added to each jar; 
these are placed on shelves, or somewhere within easy reach 
of the operator inspecting and weighing the milk as it is re- 
ceived at the factory. When all the milk delivered by a 
patron is poured into the weighing can and weighed, a small 
portion thereof, usually about an ounce, is put into the jar 
labeled with the name or number of the patron. The samples 

* Bulletin No. 9, May 1890. 



Composite Samples of Milk. 135 

are conveniently taken by means of a small tin dipper holding 
about an ounce. This sampling is continued for a certain 
number of days, a week, ten days, or sometimes two weeks, 
a portion of each patron's milk being added to his particular 
jar every time he delivered milk. Each of these composite 
samples are then tested; this test takes the place of separate 
daily tests, and gives accurate information regarding the 
average quality of the milk delivered by each patron during 
the period of sampling. The weight of butter fat which 
each patron brought to the factory in his milk during this 
time, is obtained by multiplying the total weight of milk 
delivered during the sampling period b}" the test of the 
composite sample. 

163. This method of taking composite samples has been 
proved to be practically correct. It is absolutely correct 
onl}^ when the same weight of milk is delivered daily by the 
particular patron. If this is not the case, the size of the 
various small samples should bear a definite relation to the 
milk delivered ; one-sixteen hundredth, or one-two thousandth 
of the amount of milk furnished should, for instance, be 
taken for the composite sample from each lot of milk. This 
can easily be done by means of special sampling devices 
(see 165). As the quantities of the milk delivered from day 
to day by each patron vary but little, perhaps not exceed- 
ing 10 percent of the milk delivered, the error introduced 
by taking a uniform sample, e. g., an ounce of milk, each 
time is, however, too small to be worth considering in fac- 
tory work, and the method of composite sampling described 
is generally adopted in separator creameries, and in cheese 
factories, where the payment of the milk is based on its 
quality. 



136 Testing Milk mid Its Products. 

164. By this method of composite sampling each lot of 
rich, medium or thin milk receives credit for the amount of 
butter fat which it contains, and complications that might 
arise from testing only one day's milk at irregular intervals 
are avoided. In order to obtain reliable results by com- 
posite sampling it is essential that each lot of milk sampled 
shall be sweet and in good condition, containing no lumps 
of curdled milk or small butter granules churned out. The 
milk is of course always evenly mixed before the sample is 
taken. 

165. b. Drip sample. Composite samples are sometimes 
taken at creameries and cheese factories by collecting the 
milk that drips through a small hole or tube placed in the 
conductor spout through which the milk runs from the 
weighing can to the receiving vat or tank. A small portion 
of the drip is then each day placed in the composite sample 
jar, or the quantity of drip obtained is regulated so that all 
of it may be taken. In the latter case the quantity of milk 
delivered will enter into the composite sampling as well as 
its quality, and the sample from, say 1000 lbs. of milk will 
be twice as large as the sample from 500 lbs. of milk. 

Where it is desired to vary the size of the sub-samples, 
according to the quantity of milk delivered from day to day, 
it is necessary to adopt the method of collecting drip sam- 
ples, just explained, or to make use of special sampling de- 
vices, like the " milk thief," a Scovell sampling tube, etc. 
The principle of both these tubes is the same, and it will be 
suflScient to describe here only one. 

166. c. The Scovell sampling tuhe.^ This convenient de- 
vice for sampling milk (fig. 41), consists of a drawn copper 



Kentucky experiment station, 8th report, pp. xxvi-xxxii. 



Composite Samples of Milk. 137 

or brass tube, one-half to one inch in diameter; it is open 
at both ends, the lower end sliding snugly in a cap provided 
with three elliptical openings at the side, through 
which the milk is admitted. The milk to be 
sampled is poured into a C3^1indrical pail, or the 
factory weighing can, and the tube, with the cap 
set so that the apertures are left open, is lowered 
into the milk until it touches the bottom of the 
can. The tube will be filled instantly to the 
level of the milk in the can, and is then pushed 
down, thereby closing the apertures of the cap 
and confining within the tube a column of milk 
representing exactl}^ the quality of the milk in 
the can, and forming an aliquot part thereof. 
The milk in the sampling tube is then emptied 
into the composite sample jar by turning the tube 
upside down. 

167. If the diameter of the sampling pail 
used is 8 inches, and that of the sampling tube ^ 
inch (these dimensions will be found convenient 
Fig 41 ^^ sampling milk from single cows), then the 
sampH^tJg'^ube quantity of milk secured in the tube will always 
stand in the ratio to that of the milk in the pail, of 
{\) ■ to 8 '^, * that is, very nearly 1:256; no matter how much 
or how little milk there is in the pail, the sample will repre- 
sent 256 part of the milk. For composite sampling of the 
milk of single cows, this proposition will prove about right; 
if more milk is wanted for a sub-sample, the milk to be 



*The contents of a cylinder are represented by the formula Trr^h, 
r being the radius of the cylinder, and h its height. The relation 
between two cylinders of the same height, the radii of which 
are R and r, is, therefore, as TfR^h to ;Tr'h, or as R^ to r-. 



138 Testing Milk and Its Products. 

sampled may be poured into a can of smaller diameter. If 
the mixed milk from a number of cows is to be sampled, a 
wider sampling can is used. By adjusting the diameters of 
the tube and the can, any desired proportion of milk can be 
obtained in the sample. 

For factory sampling, with a 26-inch weighing can, a tube 
three-quarters of an inch in diameter will be found of proper 
dimensions. 

168. The sampling tube will furnish a correct sample of 
the milk in the can, even if this has been left standing for 
some time; it is better, however, to take out the sample soon 
after the milk has been poured into the can, as the possible 
error of cream adhering to the side of the sampling tube is 
then avoided. 

109. The accuracy of the sampling of milk by means of 
the Scovell tube was proved beyond dispute in the breed 
tests conducted at the World's Columbian Exposition in 
1893, in which tests this method of sampling the milk pro- 
duced- by the single cows, and the different herds was 
adopted.* The data obtained in these breed tests also fur- 
nish abundant material proving the accuracy of the Babcock 
test. 

In using any one of these tubes, the size of the sample 
is regulated by the amount of milk in the sampling can, as 
the milk always rises to the same height in the tube as in 
the can. In all cases cylindrical sampling cans must be used. 

170. Composite sampling with a " one=third sam= 
pie pipette." Milk is sometimes sampled directly from 
the weighing ca,n into the Babcock test bottle by means of a 



* Kentucky experiment station, 8th report, pp. xxx-xxxi. Another form of 
a milk sampling tube in use at the Iowa experiment station is described and illus- 
trated by Mr. Eckles, in Breeder's Gazette, May 19, 1897. 



Composite Samples of Milk. 130 

pipette holding 5.87 cc, which is one-third the size of the 
regular pipette. This quantity is measured into the test bottle 
from three successive lots of milk, and the test then made in 
the ordinary manner. In this way one test shows the average 
composition of the milk delivered during three successive 
days, or deliveries. When this method is adopted, as many 
test bottles are provided as there are patrons; there is no 
need of using any preservatives for the milk in this case. 
Fig. 42 shows a convenient rack for holding the test bottles 
used in composite sampling with a "one-third sample pipette." 
Accurate results can be obtained by this method of sam- 
pling, if care is taken in measuring out the milk, and if it 
is not frozen or contains lumps of cream. It is doubtful if 
the method has any advantage over the usual method of 

composite samp- 
ling. If milk is 
delivered daily 
and each lot is 
sampled with the 
one-third pipette, 
twice or three 
times the num- 
ber of tests are 
required as when 
composite sam- 
ples are taken 
and tested once 
every week, or 
every ten days. 
This method fur- 
thermore takes 
more time in the daily sampling than the latter, as the 




;i|fiw|Mjjiw 
liiiliijiiliiiiilii 






MMMMWS 






Fig. 42. Test bottle rack for use in creameries and 
cheese factories. 



140 Testing Milk and Its Products, 

quantity of milk must be measured out accurately each 
time. If the test bottle is accidentally broken, or some 
milk spilled, the opportunity of ascertaining the fat con- 
tent of the milk delivered during the three days is lost; if 
a similar accident should occur in testing composite samples 
collected in jars, another test can readily be made. 

171. Accuracy of the described methods of sam= 
pling. An experiment made at the Wisconsin Dairy 
School may here be cited, showing that concordant results 
will be obtained by the use of the drip sampling method and 
the Scovell tube. Two composite samples were taken from 
fifty different lots of milk, amounting to about 6000 lbs. 
in the aggregate. One sample was taken of the drip from 
a hole in the conductor spout through which the milk passed 
from the weighing can; the other was taken in the weighing 
can by means of a Scovell sampling tube. The following 
percentages of fat were found in each of these samples: 

Bahcock test. Gravimetric analysis. 

Drip composite vsaiiiple 4.0 percent. 4.04 percent. 

Scovell tube composite sample.. 4.0 " 4.06 " 

Preservatives tor Composite Samples. 

When milk is kept for any length of time under ordin- 
ary conditions, it will soon turn sour and become lop- 
pered, and further decomposition shortly sets in, which 
renders the sampling of the milk both difficult and unsatis- 
factory (19). The changes which occur are due to the forma- 
tion of lactic acid through the action of bacteria on milk sugar: 
the acid in turn coagulates the casein of the milk, but does 
not destroy or attack the butter fat (27). The period dur- 
ing which milk will remain in an apparently sweet, or fresh 
condition varies, with the temperature at which it is kept. 



Coni-posite Samples of Milk. 141 

and with the cleanliness of the milk, from less than a day 
to a week or more; milk will not generally remain sweet 
longer than two days at the outside, at ordinary summer or 
room temperature. 

In order to preserve composite samples of milk in a 
proper condition for testing, some chemical which will check 
or prevent the fermentation of the milk must be added to 
it. A number of substances have been proposed for this 
purpose. 

172. Bi=chromate of potash. Of these, bichromate 
of potash is to be preferred, in the opinion of the authors, 
on account of its relative harmlessness, its cheapness and 
efficiency. The bi-chromate method for preserving samples 
of milk was proposed by Mr. J. A. Alen, city chemist of 
Gothenbuig, Sweden, in 1892,* and has been generally 
adopted in dairy regions in this countr}" and abroad. While 
not perfectly harmless, the bi-chromate is not a violent 
poison like other chemicals proposed for this purpose, and 
no accidents are liable to result from its use; at least none 
have been known to the writers to occur during the years 
that it has been used in creameries or dairies as a preserv- 
ing agent. 

173. The quantity of bi-chromate necessary for preserv- 
ing half a pint to a pint of milk for a period of one or two 
weeks is about one-half gram (nearly 8 grains). As there 
are about 900 half-grams in a pound, this quantity will suffice 
for nine weeks for a creamery having one hundred patrons, 
if tests are made once a week, or for three months (90 days), 
if tests are made every ten da3^s. 

According to Winton and Ogden,t a .22-inch pistol cart- 

* Biedermann's Centralblatt, 1892, p. 549. 

t Connecticut experiment station report 1884, p. 222. 



1^2 Testing' Milk and Its P^'odticts. 

ridge shell cut to \ inch long, or a .32-inch calibre shell cut 
to \ inch long will hold, when loosely filled, enough of pow- 
dered bi-chromate to preserve \ pint, a .32-inch calibre shell 
cut to \ inch long will hold enough to preserve one pint. 
These shells may be conveniently handled by soldering on to 
them a piece of stifl wire to serve as a handle. The amount 
of bi-chromate placed in each composite sample jar would 
fill about half the space representing one percent in the neck 
of the Babcock milk test bottle. 

174. The first portions of milk added to the composite 
sample jars containing the specified amount of bi chromate 
will be colored almost red, but as more milk is added, day 
by day, its color will become lighter yellow. The complete 
sample should have a light straw color; such samples are 
most easily mixed with acid when tested. If more bi-chromate 
is used, the solution of the casein in the acid is rendered 
diflScult and calls for more persistent shaking. Bi-chromate 
can be bought at drug stores or from dairy supply dealers at 
about 30 cents a pound, and will cost about 25 cents a pound 
at wholesale. Powdered bi-chromate of potash should be 
ordered, and not crystals, as the latter dissolve only slowly 
in the milk. Farrington's bi-chromate tablets contain the 
correct quantity of preservative for a quart sample, and will 
be found convenient; price per 1,000 tablets, $2.00. 

175. Other preservatives for composite samples. 

Among other substances recommended for use in butter or 
cheese factories as milk preservatives for composite samples 
are boracic acid compounds, formalin, chloroform, carbon bi- 
sulfid,* copper-ammonium sulfate, sodium fluorid, ammonia- 

*Delaware experiment station, eighth report, 1896, which also see for trials 
with a large number of different preservatives. 



Composite Samples of Milk. 143 

glycerin (sp. gr. 1.031), and mixtures containing mercuric 
chlorid (corrosive sublimate) with anilin color (rosanilin).* 
The coloring matter in the latter compounds is added to 
give a rose color to the sample preserved, thus showing that 
the milk is not fit for consumption; the bi-chromate giving 
naturally a yellow color to the milk, renders the addition of 
any special coloring matter unnecessary. 

None of the substances mentioned are as cheap as bi- 
chromate or more effective for the purpose for which they 
are used, when milk is to be kept not to exceed two or three 
weeks. The compounds containing corrosive sublimate are 
violent poisons, and must always be handled with the greatest 
care, lest they get into the hands of children or persons un- 
familiar with their poisonous properties; they will preserve 
the milk longer than bi-chromate when applied in sufficient 
quantities, but for factory use the latter is amply effective, 
and has, as already stated, the advantage in several other 
respects. 

176. Care of composite samples. The composite 
sample jars should be kept covered to prevent loss by 
evaporation, and in a cool place. They should be kept in the 
dark, in a special closed closet, or at least out of direct sun- 
light; the chromic acid formed by the reducing influence of 
light on chromate solutions produces a leathery cream which 
is very difficultly dissolved in sulfuric acid. 

A coating of white shellac will protect the labels of the 
composite sample jars so that they may be used for a long 
time, allowing the jars to be washed and cleaned after each 
period of testing. The shellac is applied after the names of 
the patrons have been written on the labels, and these have 



* Iowa experiment station, bulletins 9, 11, 82. 



1 44 Testing Milk and Its Products. 

been put on the jars. Gummed labels, 1x2^ in., answer this 
purpose weir. 

In keeping the milk from day to day, care should be taken 
that the cream forming on the milk does not stick to the 
sides of the jars in patches above the level of the milk. 
Unless the daily handling of the jars, and the addition of 
fresh portions of milk, be done with sufficient care, the cream 
will become lumpy, and will dry on the sides of the jars. In 
some cases it is nearly impossible to evenly distribute this 
dried cream through the entire sample so as to make the 
composite sample a true representative of the different lots 
of milk from which it has been taken. 

177. Every time a new portion of milk is added to the 
jar it should be given a gentle horizontal rotary motion, 
thereby mixing the cream already formed in the jar with the 
milk, and rinsing off the cream sticking to its side. This 
manipulation also prevents the surface of the milk from be- 
coming covered with a layer of partially dried leathery cream. 

Composite samples having patches of dried cream on the 
inside of the jar are the result of carelessness or ignorance on 
the part of the operator. If a little careful attention is given 
to the daily handling of the composite samples, the cream 
which is formed in the jars can be evenly mixed again with 
the milk without difficulty, 

178. Fallacy of averaging percentages. A compos- 
ite sample of milk should represent the average quality of 
the various lots of milk of which it is made up. This will 
invariably be true if a definite aliquot portion or fraction of 
the different lots of milk is taken. If the weights of, say 
ten different lots of milk are added together, and the sum 
divided by ten, the quotient will represent the average 



Composite Samples of Milk. 



H5 



weight per lot of milk, but the average obtained in this way 
of the tests of the different lots, may not be the correct aver- 
age test of the entire quantity of milk. The accuracy of 
such an average figure would depend on the uniformity in 
the composition and weights of the ten lots of milk. When 
there is no uniformity, the weights of the different lots of 
milk as well as their tests, must be considered. An average 
of a number of weights can be calculated directly, but not 
average percentages. The following example illustrates the 
difference between the arithmetical average of a number of 
single tests, and the true average test of the various lots. 

Methods of calculating average percentages. 



I. Milk varying in ueighh and tests. 


II. Milk of uniform weights and tesls. 


Lot. 


Weight 

of 

milk. 


Test 

of 

milk. 


Weight 
of 
fat. 


Lot. 


Weight 

of 

milk. 


Test 

of 

milk. 


Weight 
of 
fat. 


I 


lbs. 

120 

."STO 

H60 

55 

82 


per ct. 
8.5 
5,0 
5.2 
3.0 
4.0 


lbs. 
4.2 
28.5 
18.7 
1.6 
3.2 


I 


lbs. 
250 
225 
240 
238 
234 


per ct. 
4.2 
4.0 
4.3 
4.1 
4.4 


lbs. 
10.5 


II . 


II 


9.0 


Ill 


Ill 


10.3 


IV 


IV 


9.7 


v. .. 


V 


10.3 




Total 




Total 


1187 
2.37 




56.2 
11.24 


1187 
237 




49.8 


Average 

True av'ge test 


4.14 
4.73* 


Average 

True av'ge test 


4.20 

4.22t 


10.0 













56.2 X mo 

1187 



4.73. 



f 49.8 X 100 
1187 



4.22. 



179. The figures given in the table show that when the 

different lots of milk vary in test and weight, as in the first 

case, the correct average test of the 1187 lbs. of milk is not 

found by dividing the sum of these tests by five, which 

would give 4.14 percent; but the percentage which 56.2 (the 

total amount of fat in the mixed milk, in lbs.) is of 1187 
10 



146 Testing Milk and Its Products. 

(the total amount of milk, in lbs.) is 4.73, and this is the 
correct average test of the mixed milk made up of the five 
different lots. 

In the second case, the variations in both the weights of 
the different lots of milk, and their tests, are comparatively 
small, and both methods of calculation give therefore 
practically the same average test; but also in this case, the 
correct average test is found by dividing the total amount 
of fat by the total quantity of milk, making 4.22 percent, 
instead of 4.20 percent, which is the arithmetical mean of 
the five tests, the quantities of milk in the various lots do 
not enter into the calculation of the latter.* 

180. The second example represents more nearly than 
the first one the actual conditions met with at creameries 
and cheese factories. As a rule the mixed milk from a herd 
of cows does not vary more in total weight or tests, within 
a short period of time like one to two weeks, than the fig- 
ures given in this example. On account of this fact, sam- 
ples taken, for instance, with a small dipper may give per- 
fectly satisfactory results to all parties. If the different 
lots of milk varied in weight and test from day to day, as 
shown in the first case, it would be necessary to use a " milk 
thief " or a Scovell sampling tube for taking the composite 
samples, as the size of the samples taken would then repre- 
sent an exact aliquot portion of each lot of milk (166). 

181. A patron's dilemma. The following incident 
which occurred at the Wisconsin Dairy School creamery 
during the past winter, will further explain the difficulties 
met with in calculating the average tests of various lots of 
milk. 



* In the experiment given on p. 122, the arithmetical mean of the tests given is 
5.15 percent, while the true average fat content of the milk is 4.89 perceiit. 



Composite Samples of Milk. 147 

The weekly composite sample of the milk supplied by a 
patron of the creamery from his herd of 21 cows tested 4.0 
percent. One day the farmer brought to the creamery a 
sample of the morning's milk from each of his cows, and had 
them tested; after adding the single tests together, and 
dividing the sum by 21, he obtained an average figure of 
5.1 percent of fat. From this he concluded that the aver- 
age test of the milk from his cows ought to be 5.1, instead 
of 4.0, and naturally asked for an explanation. 

182. The first thing done was to show him that while 
5.1 was the correct average of the figures representing the 
tests of his twenty-one cows, it was not a correct average 
test of the mixed milk of all his cows, as he had not con- 
sidered in calculating this average, the quantities of milk 
yielded by each cow; the following illustration was used: 

Cow No. 1. yield 25 lbs. of milk, test 3.6 percent. = 0.9 lbs. of butter fat. 
Cow No. 2, yield 6 Ibg. of milk, test 5.0 percent, = 0.3 lbs. of butter fat. 

Total 31 lbs. 2)8^ 1.2 lbs. 

4.3 percent. 

The two cows gave 31 lbs. of milk containing 1.2 lbs. of 
fat; the test of the mixed milk would therefore not be 4.3 
percent (^^^|^), but ^^^ = 3.87 percent. If the fat in the 
mixed milk was calculated by the average figure 4.3 percent, 
1.33 lbs. of fat would be obtained, i. e., .13 lbs. more than 
the cows produced. 

In order to further demonstrate the actual composition 
of the mixed milk of the twenty-one cows, the milk of each 
cow was weighed and tested at each of the two milkings of 
one day. The weights and tests showed that the cows pro- 
duced the following total number of pounds of milk and fat: 



148 Testing Milk and Its Products. 

Morning milking, 113.3 lbs. of milk, containing 5.17 lbs. of fat. 
Night milking, 130.9 lbs. of milk, containing 4.98 lbs. of fat. 

The morning milk contained ' ^ — =4.56 percent of 

fat, and the night milk ^'^^^^^^ =3.80 percent of fat. 

The average of 21 tests of morning milk was 4 8 percent, 
and of 21 tests of night milk, 3.8 percent. The sum of the 
morning and night milkings gave: milk 244.2 lbs. fat 10.15 
lbs. The mixed morning and night milk, therefore, con- 
tained 10-^5X10 0^^;^ percent of fat. This is the true aver- 
244.2 

age test of the morning and night milkings of these twenty- 
one cows, as found by weighing and testing separately the 
milk of each cow at both milkings. 

183. The total milk was strained into a large can at the 
farm, both in the morning and in the evening. A sample of 
the mixed milk was taken in each case with a long- handled 
dipper as soon as the milkings were finished. When the 
cans of milk were delivered at the creamery, a sample of 
each was taken with a Scovell sampling tube. The tests of 
these four samples are given below, together with the re- 
sults from the individul tests. 

Morning milk. Night milk. 

Sample taken at the farm, with dipper.. 4.4 percent. 3.8 percent. 
Sample taken at creamery, with Scovell 

tube 4.5 percent. 3.7 percent. 

Calculated from weights and tests of 

milk from each cow 4.5 percent. 3.8 percent. 

The figures given show that practically uniform tests were 
obtained by the different methods of sampling. 

The sum of the weights of the milk from the diflerent cows 
was as follows: 



Composite Samples of Milk. 149 

Morning milk. Nitjhl milk. Daily milk . 

Total milk produced 118.3 lbs. 130.9 lbs. 244.2 lbs. 

Milk in samples 12.3 lbs. 8.9 lbs. 21.2 lbs. 

Milk for family use 2.5 lbs 2.5 lbs. 



Milk taken to creamery 98.5 lbs. 122.0 lbs. 220.5 lbs. 

It has already been shown from the weights and tests of 
each cow's milk that the herd milk contained 4.1 percent of 
fat. Multiplying the total milk delivered at the creamery, 
220.5 lbs., by 4.1 gives 9.04 lbs. of fat. The morning and 
night milkings, which were weighed and tested separately, 
contained the following quantities of butter fat. 

Morning milk 98.5 lbs. X test 4.5 = 4.43 lbs. of butter fat. 

Night milk 122.0 lbs. X test 3.8 = 4.63 lbs. of butter fat. 



Total 220.5 lbs. 9.06 lbs. 

By weighing, sampling and testing separately the morn- 
ing and night milkings of twenty-one cows, deducting the 
weight of milk in the samples, and what was taken out for 
family use, it was found that 9.04 lbs. of butter fat was sent 
to the creamery. The weights and tests of this same milk 
when delivered at the creamer}^, gave 9.06 lbs. of butter fat. 

184. This example furnishes an excellent illustration of 
the accuracy of the Babcock test, and of the closeness of 
results which may be obtained at creameries when proper 
care is taken in weighing, sampling and testing the milk. 
Similar demonstrations may be made by any factory operator, 
and with equally satisfactory results, provided that the work 
is carefully done. 



150 Testing Milk mid Its Products, 



CHAPTER XL 

CREAM TESTING AT CREAM=GATHER1NQ 
CREAflERIES. 

185. The cream delivered at gathered cream factories is 
now in many localities tested by the Babcock test, and this 
has been adopted as a basis of paying for the cream in the 
same manner as milk is paid for at separator creameries. It 
has been found to be more satisfactory to both cream buyer 
and seller, than either the oil test churn or the space (or 
gauge) systems which have been used for this purpose in 
the past. 

The details of the application of the Babcock test to the 
practical work at cream-gathering creameries have been 
carefully investigated by Winton and Ogden in Connecticut,* 
Bartlett in Maine,t and Lindsey in Massachusetts; X and we 
also owe to the labors of these chemists much information 
concerning the present workings of other systems of paying 
for the cream delivered at creameries. 

186. The space system. Numerous tests have shown 
that one si^ace or gauge of cream does no't contain a definite, 
uniform amount of fat. In over 100 comparisons made by 
Winton it was found that one space of cream I contained 

*Conn. experiment station, (New Haven) bull. No. 108 and 119; report 1894, 
pp. 214-244. 

t Maine experiment station, bull. 3 and 4 (S. S). 

J Hatch experiment station, report 1894, pp. 92-103; 1895, pp. 67-70. 

§The space is the volume of a cylinder, SJ^ inches in diameter and gf of an 
inch high. The number of spaces in each can of milk is read off before skimming 
by means of a scale marked on a strip of glass in the side of the can. (Conn. exp. 
sta., bull. No. 119). 



Cream Testing' at Creameries. 



151 



from .072 to .170 lbs. of butter fat, or on the average, .13 lbs., 
and the number of spaces required to make one pound of 
butter varied from 5.01 to 11.72. It is also claimed that in 
the winter season when the cream is gathered at long inter- 
vals, as once a week, it is necessary for the buyer to accept 
the seller's statement of the record of the number of cream 
spaces which he furnishes, since the cream cannot be left in 




Fig. 43. The oil test churn. 

the creaming cans for so long a time. These objections to 
the space system apply only to the method of paying for the 
cream, and not the manner in which the cream is obtained. 

187. The oil=test churn. As stated in the introduction, 
the oil-test churn (fig. 43), has been used quite extensively 
among gathered cream factories; this system is based on the 



152 Testing Milk and Its Products. 

number of creamery inches of cream which the various 
patrons deliver to the factory; one inch of cream contains 
113 cubic inches (i. e., a layer of cream one inch deep in a 
12-inch pail; two inches in an 8-inch pail contains 100.531 
cubic inches, two inches in an 8f-inch pail 110.18 cubic in- 
ches, and two inches in an 8|-inch pail 113.490 cubic 
inches). The driver pours the patron's cream into his 12- 
inch gathering pail, and with his rule measures and records 
the depth of the cream in the can in inches and tenths of an 
inch. The cream is then stirred thoroughly with a ladle or 
a stout dipper, and a sample is taken by filling a test tube 
from the oil test churn outfit, to the graduation mark by 
means of a small conical dipper provided with a lip. A 
driver's case contains either two or three " cards," holding 
fifteen test tubes each. The tubes as filled are placed in the 
case, and the corresponding number is in each instance re- 
corded in front of the patron's name together with the 
number of inches of cream furnished by him. 

On the arrival at the creamery the tin cards holding the 
tubes are placed in a vessel filled with water of the temper- 
ature wanted for churning (say, 60° in summer, and 65 to 70° 
in winter). When ready for churning they are placed in the 
oil-test churn, the cover of the churn put on, and the sam- 
ples churned into butter. On the completion of the churn- 
ing, the cards are transferred to water of 175-190° Fahr., 
where they are left for at least ten minutes to melt the 
butter and " cook the butter milk into a curd." The oil will 
now be seen mixed all through the mass. The test tubes 
are then re-tempered to churning temperature and churned 
again, by which process the curd is broken into fine par- 
ticles, which, when the butter is re-melted, will settle to 
the bottom. The butter is melted after the second churning 



Cream Testing at Creameries. 153 

by placing the tubes in water at 150-175° F., allowing them 
to remain therein for at least twenty minutes. If a clear 
separation of oil does not take place, the sample must some- 
times be churned three or four times until a good separation 
is obtained. A clear separation of the fat in oil test churn 
tubes is often helped by adding a little sulfuric acid to them. 

The length of the column of liquid butter fat thus separ- 
ated is determined by means of a special rule for measuring 
the butter oil; this shows the number of pounds and tenths 
of a pound of butter which an inch of cream will make; 
the first tenth of a pound on the rule is divided into five 
equal parts, so that measurements may be made to two- 
hundredths of a pound. The melted fat is measured with 
the rule, by raising the tin card holding the bottles, to about 
the height of the eye; the reading is recorded on the 
driver's tablet under Test per inch, opposite the number of 
the particular patron. The test per inch multiplied by the 
inches and tenths of an inch of cream supplied will give the 
butter yield in pounds, with which the patron will be credited 
on the books of the creamery. 

188. The objection to this system of ascertaining the 
quality of cream delivered by different patrons lies in the 
fact that it determines the churnable fat, and not the total 
fat of the cream; the amount of the former obtained is de- 
pendent on many conditions beyond the control of the pat- 
ron, viz: the acidity and the temperature of the cream, the 
size of the churn or churning vessel, etc. The same reasons 
which caused the churn to be replaced by methods of deter- 
mining the total fat of the milk, in the testing of cows 
among dairymen and breeders, have gradually brought 
about the abandonment of the oil test in creameries, and the 
adoption of the Babcock test in its place. 



154 Test in o Milk and Its Products. 

189. The Babcock test for cream. Both the space 
system and the oil test churn used for estimating the quality 
of cream at creameries have now largely been replaced by 
the Babcock test in the more progressive creameries in this 
country, and composite samples of cream are collected and 
tested in a similar manner as is done with milk at separator 
creameries and cheese factories. 

A very satisfactory method of arrangements for working 
the Babcock test, which is in use in many Eastern cream- 
eries, is described by Winton and Ogden in the Connecticut 
report, previously referred to. The cream gatherer who 
collects the cream in large cream cans is supplied with a 
spring balance (1, see fig. 44), pail for sampling and weigh- 
ing the cream (2), sampling tube (3), and sample bottles (5). 
At each patron's farm he takes from his wagon the sampling 
pail and tube, the scales, and one small collecting bottle. He 
should find in the dairy of the patron the cans of perfectly 
sweet cream, kept at a temperature of 40° to 50° F., and 
protected from dirt and bad odors. Either sour or frozen 
cream must be rejected. The patron's number should be 
painted in some conspicuous place near the cream cans in 
his dairy house. The gatherer hangs the scale on a hook 
near the cream to be collected; the scale should be so made 
that the hand of the dial will stand at zero when the empty 
pail is hung on it. The cream is then poured at least twice 
from one can to another in order to mix it thoroughly.* 



* The necessity of care in mixing the cream is shown by the following illustra- 
tion given hy the authors referred to : 

Percent of fat in cream which stood for 24 hours. 



j^'ot mixed 


Surface. 
28.0 


Bottom. 
5.0 

22.0 


Sample drawn 
with sampling tube 
19.25 




23.75 


22.50 


Poured twice 




22.25 



Cream Testino- at Crecnuer 



1CS. 



155 




11 8 7 6 5 

Fig. 44. Outfit for cream testing by the Babcock test at gathered cream factories. 

190. When properly mixed, the cream is poured into 
the weighing pail, and is weighed and sampled. The 
authors give the following description of the cream samp- 
ling tube used, and directions for sampling and weighing 
the cream. 



156 Testing Milk and Its Products. 

''Sampling T«6e.— This tube, devised by Mr. Ogden, is of stout 
brass, about ^^ of an inch thick, and a few inches longer than the 
weighing pail which is used with it. On the upper end, a small 
brass stop-cock of the same bore is fastened. It should be nickel 
plated inside and out, to keep the metal smooth and free from 
corrosion. These tubes maybe obtained from less than f^ to over 
14 inch bore. The greater the diameter of the weighing pail, the 
wider should be the bore of the tube. For use with pails 8 inches 
in diameter, a y% i^^'b bore sampling tube will serve the purpose, 
but when the pail has a diameter of 9 or more inches, a tube with 
a bore of ^A inch or more should be used. It must be borne in 
mind that doubling the diameter of the pail, or of the sampling 
tube, increases the capacity fourfold. 

The tube when not in use should be kept in an upright position 
to permit draining. 

''Sampling and Weighing. — Lower the sampling tube with the 
cock open, to the bottom of the weighing pail which holds the 
mixed cream. When it is filled, raise it out of the liquid and allow 
it to drain for a few seconds. By this. means the tube is rinsed 
with the cream to be sampled and any traces of cream adhering 
to the tube from previous use are removed. With the cock still 
open, slowly lower the sampling tube to the bottom of the cream 
pail. After allowing a moment for the cream to rise in the tube 
to the same height as in the pail, close the cock and raise the 
sampler carefully out of the cream. As long as the cock is closed, 
the cream in the tube will not flow out, unless the tube is strongly 
jarred. Allow the cream adhering to the outside of the tube to 
drain off for a few seconds, then put the lower end into the 1 to 
IV2OZ. wide-mouth glass collecting bottle which bears the patron's 
number on its cork, and open the cock. The cream will then flow 
out of the sampler into the bottle, which is afterwards securely 
corked and put into the cream-gatherer's case. Immediately 
weigh the cream in the cream pail to the quarter or half pound, 
as may be judged expedient, and record the weight. 

" If the patron has more than one pailful, repeat with each pail- 
ful the operation of sampling and weighing, putting all the sam- 



Ci'cam Testing- at Creameries, 



157 



pies in one and the same bottle. Weigh, all cream collected, in 
one and the same sampling pail and draw a sample from each 
separate portion v\reighed.^' 

191. After sampling and weighing each patron's cream 
it is poured into the driver's large can, and the sample bot- 
tles are carried in a case to the creamery where the con- 
tents of each are poured into the composite sample jar of 
the particular patron. The accompanying illustration (fig. 
45) shows an arrangement for keeping the composite sample 
jars in the testing room of the creamer}^ 

192, The samples of cream in the small bottles, besides 
furnishing the means of testing the richness of the cream, 




Fig. 45. Case for holding composite sample bottles at creamery. 



158 Testing Milk and Its Products. 

give the creamery owner or manager an opportunity to in- 
spect the flavor of each lot of cream, and the condition in 
which it has been kept by the various patrons. Potas- 
sium bi-chromate is placed in the composite sample jars, 
and these are cared for and tested in the same manner as 
composite samples of milk (176). 

193, The collecting bottles should be cleaned with cold, 
and afterwards with hot water, as soon as they are emptied, 
and before a film of cream dries on them. When washed 
and dried, these bottles are placed in the cases, ready for 
the next collecting trip. There can be no confusion of bot- 
tles since the corks and not the bottles are marked with the 
numbers of the respective patrons. 

194:. When cream is bought by this system of testing 
composite samples, the patrons are paid for the number of 
butter fat contained in their cream, in exactly the same way 
as milk is paid for at separator creameries. It makes no 
difference how thick or how thin the cream may be, or how 
much skim milk is left in the cream when brought to the 
factory. Eighty pounds of cream containing 1 5 percent of 
fat will bring no more or less than 48 pounds of cream 
testing 25 percent; in either case 12 pounds of pure butter 
fat is delivered, which will make the same amount of butter 
in both cases, viz: toward 14 lbs., and both patrons should 
therefore receive the same amount of money. 

There is a small difference in the value of the two lots of 
cream to the creamery owner or the butter maker, in favor 
of the richer cream, both because its smaller bulk makes the 
transportation and handling expenses lighter, and because 
slightly less butter fat will be lost in the butter milk, a 
smaller quantity of this being obtained from the richer 
cream. But it is doubtful if the differences thus occurring 



Cream Testing at Creameries, 15^ 

are of sufficient importance to be noticed under ordinary 
creamery conditions; the example selected presents an ex- 
treme case of variation in the fat content of cream. A trial 
of this system at five Connecticut creameries, supplied mostly 
with Cooley cream, by over 175 patrons, showed that the 
average composition of the cream from the different patrons 
varied only from 16.9 to 19.8 percent fat. The cream of 
some patrons on certain days contained only 9.5 percent of 
fat, and other patrons at times had as high a test as 30 per- 
cent., but these great differences were largely evened up 
when the average quality of the cream delivered during a 
period of time, like a month or more, was considered. 

195. Smaller differences in the composition of cream 
will, however, always occur, even if the same system of set- 
ting the milk, like the cold deep-setting process, is used, and 
the water is kept at the same temperature at all times. This 
is due to differences in the composition of the milk and its 
creaming qualit}^; whether largel}' from fresh cows or from 
late milkers; whether kept standing for a time before being 
set or submerged in the creamer immediately after milking 
and straining; diameter of creaming cans, etc. Bartlett 
states^ that the percentage of fat in the cream from the 
same cows may be increased ten percent or more by keeping 
the water at 70° instead of at 40° F. The higher temper- 
ature will give the richer cream, but the separation will not 
be so complete, since a richer skim milk is obtained from 
the milk set at the higher temperature. Separator cream is 
not materially influenced by the conditions mentioned, as 
the separator can be regulated to deliver cream of nearly 
uniform richness from all kinds of sweet milk. 



* Maine experiment station, bulletin No. 3 (S. S). 



i6o Testing Milk and Its Products. 



CHAPTER XII. 
CALCULATION OF BUTTER AND CHEESE YIELD. 

A. — Calculation of Yield of Butter. 

196. Butter fat test and yield of butter. The Bab- 
cock test shows the amount of pure butter fat contained in 
a sample of milk or other dairy products. The butter ob- 
tained by churning cream or milk contains, in addition to 
pure butter fat, a certain amount of water, salt and curd. 
While an accurate milk test gives the total quantity of but- 
ter fat which there is in the sample of milk or cream tested, 
the churn cannot be depended upon either to leave the same 
amount of butter fat in the butter milk or to include the 
same amount of water, salt and curd in the butter at each 
churning. 

If a quantity of milk, say 3000 lbs., be thoroughly mixed 
in a vat, and then divided into half a dozen equal portions, 
a Babcock test of the different lots will show the same per- 
centage of butter fat in each portion. If, on the other hand, 
each of these lots be skimmed, and the cream ripened in 
different vats and churned separately, the same weight of 
butter from each lot of 500 lbs. of milk will not be obtained, 
even by the most expert butter maker, or if all the opera- 
tions of skimming, cream ripening, churning, sailing and 
butter-working were made as nearly uniform as possible. 
Careful operators can handle the milk and cream so that 
very nearly the same proportion of the fat contained in the 



Calculation of Butter and Cheese Yield. i6i 

milk is recovered in the butter in different churnings, but 
since the water in butter is held mechanicall}-, and is not 
chemically combined with it, the amount retained by the 
butter is quite variable in different churnings, especially 
since the laws governing the retention of water in butter are 
but imperfectly understood. 

197. Variations in the composition of butter. As 

an illustration of the variability of butter in its composition, 
the analyses of the butter made in the breed tests at the 
World's Fair in 1893, may here be cited; the butter was in 
all cases made by as nearly identical methods and under as 
uniform conditions as could possibly be obtained by the 
skilled operators having this work in charge; the average 
composition of 350 samples of this butter, with upper and 
lower limits, was as shown in the following table. 

Composition of samples of butter, World's Fair, 1893. 





Water. 


Fat. 


Curd. 


Salt and 
ash. 


Sum of water, 
curd, salt 
and ash. 


Average of 350 analy- 
ses 


Percent. 

11.57 

8.63-15.00 


Percent. 
84.70 
76.53-88.26 


Percent. 

.95 

.50-2.14 


Percent. 

2.78 

1.01-8.58 


Percent. 
15 30 


Lower and upper lim- 
its 









Analyses of fifty samples of creamery butter taken from 
the tubs ready for market at as many Wisconsin creameries, 
in 1896, indicated that no two of them were exactly alike in 
composition, but varied within the limits given below.* 



* Wisconsin experiment station, bull. 56. 
11 



l62 



Testing Milk and Its Products. 



Summary of analyses of Wisconsin creamery butter. 



Water. 



Butter 
fat. 



Curd. 



Salt 
and ash. 



Sum of 
water, salt 
and curd. 



Highest. 
Lowest . 
Average 



Percent. 

17.03 
9.18 
12.77 



Percent 

87.50 
77.07 
83.08 



Percent. 

2.45 
0.36 

1.28 



Percent. 



4.73 
1.30 

2.87 



Percent. 

22. 95 
12.50 
16.92 



The preceding analyses show the composition of butter 
made at one place where every possible effort was taken to 
produce a uniform product, and of butter made at fifty dif- 
ferent creameries, where there was more or less variation in 
the different operations of manufacture, and in the appli- 
ances and machinery used. The majority of the samples of 
butter analj^zed were, in either case, naturally of, or very 
near, the average composition given, but since there is such 
wide variations in the composition of the butter made by 
the uniform methods adopted in the World's Fair breed tests, 
butter of a more uniform composition cannot be expected 
from the thousands of different creameries and private 
dairies which supply the general market with butter. 

The analyses of the fifty samples of creamery butter, 

given above, show that the content of the butter fat varied 

from 77 to over 87 percent, and according to the average of 

the analyses, 83 pounds of butler fat was contained in, or 

made, 100 lbs. of butter. There was, therefore, in this case 

produced 20.5 percent more butter than there was butter 

fat, since 

83:100 : :100:x; therefore 



100X100 
83 



120.5. 



Calculation of Butter and Cheese Yield. 163 

198. "Overrun " of churn over test. The yield of 
butter is not, however, as a rule compared with the amount 
of butter fat contained in the butter, but with the total but- 
ter fat of the whole milk from which it was made. This 
"increase of the churn over the test" is what is generally 
called the overrun in creameries. 

The overrun obtained in different creameries, or even in 
the same creameries at different times, will be found to vary 
considerably. When the milk is accurately tested, and the 
butter well worked, this overrun will vary from 10 to 16 per- 
cent; that is, if a quantity of milk contains exactly 100 lbs. 
of butter fat, as found by the Babcock test or any other ac- 
curate method of milk testing, from 110 to 116 lbs. of butter 
ready for market may be made from it. 

Variations will occur in the speed of the separator, in the 
conduct of the ripening and the churning processes, and in 
the condition of the butter when the churn is stopped, even 
under the very best of care and attention to details; and abso- 
lutely uniform losses of fat in skim milk and butter milk, or 
the same water content of the butter cannot, therefore, be 
expected. 

199. Factors influencing the overrun. The overrun 
is influenced by two factors: the losses of butter fat sus- 
tained in separating the milk and churning the cream, and 
the gain due to the admixture of water, salt, etc., in the 
manufacture of butter. Considering first the losses of fat 
in skim milk and butter milk, the separator usually, when 
run at normal capacity, will leave the same percent of fat in 
skim milk, whether rich or poor milk is skimmed; an excep- 
tion to this may be found in separating rich milk having 
large fat globules, or milk from fresh milkers, in either of 



164 Testing Milk and Its Products. 

which cases the large size of the fat globules occasions a 
more complete separation of fat by the centrifugal force. But 
generally speaking, the statement holds good that the total 
loss of fat in separator skim milk is a factor of the quantity 
of milk run through the separator, rather than of its quality. 
It follows from this, however, that the relative losses of fat in 
skim milk will vary to some extent according to the quality 
of the milk separated. Selecting two extremes in the quality 
of milk, 2.5 and 6.0 percent of fat, there will be found, say 
.2 percent of fat in the skim milk from either lot, provided the 
separator is not unduly crowded, and the separation is con- 
ducted under normal conditions in either case. But .2 per- 
cent fat makes 8 percent of the total fat in the poor milk 

/— ^ 00 = 8), and only 3 percent of that in the rich milk. 

It takes 4000 lbs. of the 2.5 percent milk to furnish 100 lbs. 
of fat, and only 1666 lbs. of the 6 percent milk; in skim- 
ming the poor milk, a loss of .2 percent of fat is sustained in 
the skim milk from 4000 lbs. of milk, while in the rich milk 
a similar loss is sustained in the skim milk from only 1666 
lbs. of milk. 

The example gives an extreme case, and one not likely to 
be met with in practice. The range in the richness of the 
milk delivered by different patrons at the factory is usually 
within one-half a percent of fat. In such cases the propor- 
tion of fat lost in skimming does not vary much, e. g., in 
case of milks containing 3 5 and 4 percent of fat, and varia- 
tions in the overrun occurring when the proper care in skim- 
ming, ripening and churning is taken, are due, therefore, 
primarily to differences in the water content of the butter 
made (197). 



Calculation of Butter and Cheese Yield. 165 

200. The losses from very poor, very rich and average 
milk, as received at creameries and cheese factories, can be 
traced from the following statement; this gives the quantities 
of fat lost in handling milk of four grades, viz: 2.5, 3.5, 4.0 
and 6.0 percent, in case of each grade calculated to a stand- 
ard of 100 lbs. of fat in the milk. 

To supply 100 lbs. of fat would require the following 
amounts of the different grades ot milk: 

4000 lbs. of milk testing 2.5 percent will contain 100 lbs. of fat. 
2857 " " " 3.5 " " '* 100 " " 

2500 •' " " 4.0 " •* " 100 " " 

1666 " " " 6.0 ♦' " " 100 " " 

Assuming that the skim milk contains .2 percent of fat 
and makes up 80 percent of the whole milk, and that the 
butter milk tests .3 percent, and forms 20 percent of the 
whole milk, the butter fat record of the quantities of differ- 
ent grades of milk containing 100 lbs. of fat will appear as 
follows: 

Fat available for butter in different grades of milk. 



Grade of milk. 


Whole milk. 


Skim milk. 


Butter milk. 


Total 
loss. 


Fat 
available 

for 
butter. 


2 5 percent 


4000 ftx 
2.5 perct. 


320C ft). 
.2 per ct. 


800 ft). 
.3 perct. 


ft. 

8.8 
6.3 
6.5 
3.6 


Percent. 






Fat 


100 ft). 

2857 ft). 
3. 5 perct. 


6.4 ft). 

2285 ft). 
. 2 per ct. 


2.4 ft). 

572 ft). 
. 3 per ct. 


91.2 


3 5 percent 








Fat 


100 ft). 

2500 ft). 
4 perct. 


4.0 ft). 

2000 ft). 
.2per ct. 


1.7 ft). 

500 ft). 
.3 perct. 


93.7 










Fat 


100 ft). 

1666K ft). 
6 perct. 


4.0 ft). 

1.S33 ft). 
.2 perct. 


1.5 ft. 

333 ft. 
.3 perct. 


94.5 


6 percent ......... 








Fat 


100 ft). 


2.6 ft). 


1.0 ft. 


96.4 







1 66 Testing Milk and Its Products. 

The table shows that with 2.5 percent milk, there is a loss 
of 6.4 lbs. of fat in the skim milk and 2.4 lbs. of fat in the 
butter milk for every 100 lbs. of fat in the whole milk, or a 
total loss of 8.8 lbs. from these sources. In case of 6 per- 
cent milk these losses are 2.6 lbs. and 1.0 lbs. for skim milk 
and butter milk, respectively; a total loss of 3.6 lbs., or 5.2 
lbs. less than the losses with the very poor milk. This 
difference in the losses between 3.5 percent and 4.0 percent 
milk shrink to only .8 pound of fat when a quantity of 
milk containing 100 lbs. of fat is handled in both cases. 

The overrun from each of the four grades of milk can be 
calculated to butter containing a certain percent of fat. The 
fat content of butter varies greatly, as has been shown 
(197); assuming it to be 83 percent, on the average, the 
quantity of butter obtained from the 100 lbs. of fat, or 
rather from the portion thereof which is available for butter, 
in each case would be as follows : 

Butter cont. 
Available fat. SSprct.fat. 
100 lbs. of fat from 4000 lbs. of 2.5 pr ct. milk, 91.2 lbs.=109.61bs. 
100 " " " 2857 " 3.5 '' " 93.7 " =112.9 lbs. 

100 " " '' 2500 " 4.0 " " 94.5 " =113.8 lbs. 

100 " " " 1666 " 6.0 " " 96.4 " =116.1 lbs. 

The overrun in each case would be: 

For 2.5 percent milk = 109.6 — 100= 9.6 percent. 

3.5 " " =112.9 — 100 = 12.9 

4.0 " " =113.8 — 100 = 13.8 

6.0 " " =116.1 = 100 = 16.1 
All butter makers should obtain more butter from a cer- 
tain quantity of milk than the Babcock test shows it to con- 
tain butter fat, but it is impossible to know exactly how 
much butter fat is lost in the skim milk and the butter milk, 
unless these products are tested, and how much water, salt 
and curd the butter will contain. 



Calculation of Butter and Cheese Yield. 167 

201. Calculation of overrun. The overrun is calcu- 
lated by subtracting the amount of butter fat contained in 
a certain quantity of milk, from the amount of butter made 
from it, and finding the percent which this difference is of 
the amount of butter fat in the milk. 

Example. 8000 lbs. of milk is received at the creamery on a 
certain day; the average test of the milk is 3.8 percent. 340 lbs. of 
butter was made from this milk, as shown by the weights of the 
packed tubs. By a simple multiplication we find that the milk 
contained 8000X. 038=304 lbs. of butter fat. The diflference be- 
tween the weight of butter and butter fat, is, therefore, 36 lbs.; 

36 is — — — — =11.8 percent of the quantity of butter fat in the 

o04? 

milk; that is, the overrun for the day considered was 11.8 percent. 

The formula for the overrun is as follows: 

(b — f) 100 
X— ^ 

h and / designating the quantities of butter and butter fat, 

respectively, made from or contained in a certain quantity of 

milk. In the preceding example, the calculation would be as 

-p^ii^ « (340 — 304) 100 -,. o . 

lollows : ^^ -—— =11.8 percent. 

202. Conversion factor for butter fat. A committee 
of the Association of American Agricultural Colleges and 
Experiment Stations reported at the ninth annual conven- 
tion of the Association that " in the ninety-day Columbian 
Dairy Test, 96.67 percent of the fat in the whole milk was 
recovered in the butter. This butter on the average contained 
82.37 percent butter fat; in other words, 117.3 pounds of but- 
ter were made from each 100 pounds of butter fat in the 
whole milk.* The exact conversion factor would be 1.173. 



* When 82.37 lbs. of butter fat will make 100 lbs. of butter, how much butter 
will 96.67 lbs. of butter fat make? 82.37:96.67 :: 100: x. x = 117.3. 



1 68 Testing Milk and Its Products. 

As this is an awkward number to use, and as li is so nearly 
the same ... it has seemed best to recommend that 
the latter be used as the conversion factor." 

A resolution was adopted by this association recommend- 
ing that the approximate equivalent of butter be computed 
by multiplying the amount of butter fat by \\. 

These figures represent more than ordinary care in testing, 
skimming and churning, and probably the minimum loss of 
fat in the manufacturing processes. The increase of churn 
over test represented by one-sixth, or 16 percent, therefore 
may be taken as a maximum " overrun." Butter makers who 
report overruns of 16-20 percent do not show their expert- 
ness in butter making by such high figures, but their lack of 
accuracy in testing, or carelessness in working the butter; a 
large overrun may be obtained both by reading the test too 
low, and by leaving an excess of water in the butter through 
insuflScient working or other causes. 

203. Butter yield from milk of different richness. 

a. Use of hutter chart. The approximate yield of butter 
from milk of different richness is shown in table IX in the 
Appendix. This table is founded on ordinary creamery ex- 
perience and will be found to come near to actual every-day 
conditions of creameries where modern methods are followed 
in the handling of the milk and its products. The table has 
been prepared in the following manner: 

It is assumed that the average loss of fat in the skim milk 
is .20 percent, and that 85 lbs. of skim milk is obtained 
from each 100 lbs. of whole milk; to this loss of fat is added 
that taking place in the butter milk; about 10 lbs. of butter 
milk is obtained per 100 lbs. of whole milk, testing on the 
average .30 percent. 



Caladation of B titter and Cheese Yield. 169 

If / designate the fat in 100 lbs. of milk, then the fat 
recovered in the butter from 100 lbs. of milk will be 

f-(foX.20+^,X.3o)=f-.20 

There is, on the other hand, an increase in weight in the 
butter made, owing the admixture of non-fatty components 
therein, principally water and salt. Butter packed and 
ready for the market will contain in the neighborhood of 
84 percent of fat (197), so that the fat recovered in the but- 
ter must be increased by Vf = 1.19. If B therefore desig- 
nate the yield of butter from 100 lbs. of milk, the following 
formula will express the relation between yield and fat con- 
tent, provided there are no other factors entering into the 

problem, viz: 

B = (f — .20) 1.19 

Certain mechanical losses are, however, unavoidable in 
the creamery, as in all other factory operations, viz: milk and 
cream remaining in vats and separators, butter sticking to 
the walls of the churn, etc. These losses have been found 
to average about 3 percent of the total fat in the milk 
handled, under normal conditions and under good manage- 
ment (202) ; we therefore deduct this percent from the pre- 
ceding value for B, and have: 

B=(f_.20)1.16 

204. Table IX in the Appendix, founded on this formula, 
may be used to determine the number of pounds which the 
milk delivered by the various patrons within the limits of 
3 and 5.3 percent will be likely to make. It presupposes 
good and careful work at the separator, churn and butter 
worker, and will generally under such conditions show yields 
of butter varying but little from those actually obtained. 
It may also be conveniently used by the butter maker or 



170 Testing- Milk and Its Products, 

the manager to check the work in the creamery; the aver- 
age test of the milk received during a certain period is found 
by dividing the total butter fat received by the total milk, 
multiplying by 100; the amount of butter which the total 
milk of this average fat content will make according to the 
table, is then compared with the actual churn yield. 

Example. A creamery receives 200,000 lbs. of milk during a 
month; the milk of each patron is tested and the fat contained 
therein calculated. The sum of these amounts of fat may be 7583 
lbs.; the average test of the milk is then 3.79 percent. Ac- 
cording to table IX, 10,000 lbs. of milk, testing 3.8, will make 
421.2 lbs. of butter, and 200,000 lbs., therefore, 8424 lbs. of but- 
ter. The total quantity of butter made during the month should 
not var3' appreciably from this figure. 

205. b. Use of overrun table. The table referred to above 
gives a definite calculated butter yield for each grade of 
milk, according to the average creamery conditions. As it 
may be found that this table will either give uniformly too 
low or too high results, table X in Appendix is included, by 
means of which the butter yield corresponding to overruns 
from 10-20 percent may be ascertained in a similar way as 
above described. 

The total yield of butter is divided by the total number 
of pounds of fat delivered; the quotient will give the amount 
of butter made from one pound of fat, and this figure mul- 
tiplied by the fat delivered by each patron shows the pounds 
of butter to be credited to each patron. To use the table, 
find in the upper horizontal line the number corresponding 
most nearly to the number of pounds of butter from one 
pound of fat. The vertical column in which this falls gives 
the pounds of butter from 100 lbs. of milk containing the 
percents of fat given in the outside columns (Babcock *). 



*Woll, Handbook for Farmers and Dairymen, p. 273. 



Calculation of Butter and Cheese Yield. 171 

B. — Calculation of Yield of Cheese. 

206. a. From fat. The appropriate yield of green Ched- 
dar cheese from 100 lbs. of milk may be found by multiply- 
ing the percent of fat in the milk by 2.7: if / designate the 
percent of fat in the milk, the formula will, therefore, be: 

Yield of cheese = 2. 7 f (I) 

The factor 2.7 will only hold good as the average of a 
large number of cases. In extensive investigations during 
three consecutive years. Van Slyke * found that the number of 
pounds of green cheese obtained for each pound of fat in 
the milk varied from 2.51 to 3.06, the average figures for the 
three years 1892- '94, incl., being 2.73, 2.71, and 2.72 lbs., 
respectivel}'. The richer kinds of milk will produce cheese 
richer in fat, and will yield a relatively a larger quantity of 
<iheese, pound for pound, than poor milk, for the reason 
that an increase in the fat content of milk is accompanied 
by an increase in the other cheese-producing solids of the 
milk.t The preceding formula would not, therefore, be cor- 
rect for small lots of either rich or poor milk, but only for 
milk of average composition, and for large quantities of 
normal factory milk. For cured cheese the factor will be 
somewhat lower, viz: about 2.6, on the average. 

207. b. From solids not fat and fat. If the percent- 
ages of solids not fat and of fat in the milk are known, the 
following formula by Babcock will give close results: 

Yield of green cheese = 1.58 (^+ .91 f) . . (II) 

*N. Y. experiment station, (Geneva), bulletins No. 65 and 82. 

t Investigations as to the relation between the quality of the milk and the 
yield of cheese have been conducted by a number of ex])eriment stations; the fol- 
lowing references give the main contributions published on this point: N. Y. 
(Geneva) exp. sta., reports 10-13, incl.; Wis. exp. sta., reports 11 and 12; Ont. Agr. 
College, reports 1894- '95, incl.; Minn. exp. sta., reports 1892- '94, incl ; Iowa exp* 
sta . bull. 21. 



172 Testing Milk and Its Products. 

s being the percent of solids not fat in the niilk, and / the 
percent of fat. 

The derivation of this formula is as given below.* 

Cheese is made up of water, fat and casein, with small quanti- 
ties of other milk solids, and also salt and a Httle cheese color ad- 
ded in the process of manufacture. The green cheese as taken from 
the press, will contain in the neighborhood of 37 percent of 
water.f The total quantity of solids other than fat in the cheese 
has been found equal to one-third of the solids not fat in the 
milk from which the cheese is made. The fat contained in the 
cheese is that found in the milk less the fat lost in the process of 
manufacture, i. e., in the whey and the drippings. In the manu- 
facture of Cheddar cheese very nearly 9 percent of the fat in the 
milk is lost ; a little less than 9 percent has been found in case of 
very rich milks, and a trifle more with poor milks, but this may 
be considered a correct average figure. The quantity of cheddar 
cheese made from 100 lbs. of milk will therefore be found by add- 
ing one-third of the percent of solids not fat in the milk to 91 per- 
cent of the fat, and multiplying the sum by V's*, or 1.58. The for- 
mula then is 

Yield of green cheddar cheese 

from 100 lbs. of milk = 1.58 (^ + 91 f. j 

The solids not fat can be readily ascertained from the lac- 
tometer reading and the percent of fat, as shown on p. 87, 
b}^ means of table V, given in the Appendix. 

Table XI in the Appendix gives the yield of cheese from 
100 lbs. of milk containing from 2.5 to 6.0 percent fat, the 
lactometer readings of which range between 26 and 36. By 
means of this table cheese makers can calculate very closely 
the yields of cheese which certain quantities of milk will 
make; as it takes into consideration the non-fatty solids as 



* Wisconsin experiment station, twelfth report, p. 105. 

t N. Y. (Geneva) experiment station, twelfth report, p. 485. 



Calculation of Butter and Cheese Yield. 173 

well as the fat of the milk, the results obtained by the use 
of this formula will be more correct than those found by 
means of formula (I). The uncertain element in the for- 
mula lies in the factor 1.58, which, as shown above, is based 
on an average water content of 37 percent in the green 
cheese. This may, however, be changed to suit any partic- 
ular case, e. g,, 35 percent (^5*^ = 1.54), 40 percent (Vo* = 1.67) 
etc. The average percentages of water in green cheese 
found by A^an Slyke in his investigations referred to above, 
were for the years 1892-'94, respectively, 36.41, 37.05 and 
36.70 percent. 

208. c. From casein and fat. If the percentages of 
casein and fat in the milk are known, the yield of cheese 
may be calculated by the following formula, also prepared 
by Dr. Babcock: 

Yield of cheese = 1.1 f + 2.5 casein .... (Ill) 

This formula will give fairly correct results, but no more 
so than formula (II) ; it is wholly empirical. 



174 Testing Alilk and lis Products. 



CHAPTER XIIL 
CALCULATING DIVIDENDS. 

A. — Calculating Dividends at Creameries. 

209. The simplest method of calculating dividends at 
creameries is to find the weight of butter fat in pounds 
delivered to the creamer}^ by each patron for a certain 
length of time, and then multiply this amount by the price 
per pound of fat. Farmers are usually paid once a month 
for their milk at the factory. Each lot of milk is weighed^ 
when delivered at the creamery, and a small quantity thereof 
is saved for the composite sample, as previously explained 
under composite tests (134). Some creameries test these 
samples at the end of each week, and others after collecting 
them for ten days or two weeks. If the four weekly 
composite samples of a patron's milk tested 3.8, 4.0, 3.9, 
4.1 percent., these four tests are added together, and the 
sum divided by 4; the result, 3.75 percent, is used as the 
average test of this milk. By multiplying the total number 
of pounds of milk delivered by this patron, by his average 
test, the total weight in pounds of butter fat delivered to 
the factor}^ during the month is obtained. This weight of 
fat is then multiplied by the price to be paid by the cream- 
ery per pound of butter fat; the product shows the amount 
of money due this patron for the milk delivered during the 
time samples were taken. 

210. Price per pound of butter fat. The method 
of obtaining the price to be paid for one pound of butter 



Calculating Dividends. 175 

fat varies somewhat in different creameries, on account of 
the various ways of paying for the cost of manufacturing 
the butter. The method to be followed is generally deter- 
mined by agreement between the manufacturer and the 
milk producers, in case of proprietary creameries, or be- 
tween the shareholders, in co-operative creameries. The 
following methods of paying for the cost of manufacture 
are at the present time met with in American creameries: 

211. I. Proprietary creameries, a. When the cream- 
ery is owned by some one person or compan3\ the owner or 
owners agree to make the butter for 3 or 4 cents a pound; 
the difference between the total receipts of the factory and 
the amount due the owner is then divided between the dif- 
ferent parties, according to the amount of butter fat con- 
tained in the milk delivered by them. 

In the majority of cases, the price charged for making 
butter is now 4 cents a pound; 3f and 3|^ cents are sometimes 
charged. The larger the amount of milk received at a fac- 
tory, the lower will naturallj^ be the cost of manufacturing 
the butter.* 

b. The proprietor of the creamerj^ sometimes agrees to paj^ 
a certain price for 100 lbs. of milk delivered, according to 
its fat content, the price of milk containing 4 percent of 
butter fat being the standard. This price may change during 
the different seasons of the year by mutual agreement. 

c. A creamery owner may offer to pay 1 to 2 cents, usually 
\\ cents, below the average market price of butter, for each 
pound of butter fat received in the milk. 

212. II. Co=operative creameries. In this case, where 
the creameries is owned by the patrons, one of the stockholders- 



* Wisconsin experiment station^ bull. 56, p. 26. 



176 Testing Milk and Its Products. 

who is elected secretary attends to the details of running 
the factory and selling the product. His accounts show the 
amount of money received each month for the butter and 
other products sold, and the expenses of running the factory 
during this time. The expenses are subtracted from the re- 
ceipts, and the balance is divided among the patrons, each 
one receiving his proportionate share according to the 
amounts of butter fat delivered in each case (as shown by 
the total weight and the average tests of the milk delivered 
during this time). 

In nearly all cases, the farmers receive about eighty pounds 
of skim milk for each hundred pounds of whole milk they 
deliver to the factory, in addition to the amount received 
for the milk, calculated according to one or the other of the 
preceding methods. 

213. Illustrations of calculations of dividends. In 

order to illustrate the details of calculating dividends, or 
the amount to be paid each patron for the milk supplied 
each month, when payments are made by each of the four 
systems given, it will be assumed that a creamery receives 
5000 pounds of milk daily for thirty days, and makes 6650 
lbs. of butter from the 150,000 lbs. of milk received during 
this time. The average test of this milk may be found by 
multiplying the total weight of milk delivered by each pa- 
tron by his average test, and dividing the sum of these pro- 
ducts by the total weight of milk received at the creamery, 
(in the example given, by 150.000) the quotient being multi- 
plied by 100. Such calculations may show that, e. g., 5700 
lbs. of butter fat have been received in all in the milk 
delivered by the different patrons; this multiplied by 100, 
and divided by 150,000 gives 3.8 as the average test, or the 



Calculatino' Dividends. 



^17 



average amount of butter fat in each 100 lbs. of milk re- 
ceived during the month. 

So far, the method of calculation is common for all differ- 
ent systems of payment given above; the manner of pro- 
cedure now differs according to the agreement made between 
owner and patrons, or between the shareholders, in case of 
co-operative creameries. 

214. la. If the net returns for the 6650 lbs. of butter 
sold during the month were $1197, and the creamery is to 
receive 4 cents per pound of butter as the cost of manufac- 
ture, etc., the amount due the creamery is 6650X.04=$266, 
and the patrons would receive $1197— $266=$931. This sum, 
$931, is to be paid to the patrons for the 5700 lbs. of butter 
fat, which, as shown above, was the weight of fat contained 
in the 150,000 lbs. of milk delivered during the month. 
The price of one pound of butter fat is then easily found: 
$931^5700=16^ cents. This price is then paid to all pa- 
trons for each pound of butter fat delivered in their milk 
during the month. The monthly milk record of three pa- 
trons may, e. g., be as given in the following table: 



PATRON. 


FIRST WEEK 


SECOND WEEK 


THIRD WEEK 


FOURTH WEEK 


Total 

Milk 
lbs. 


h 


Milk 

lbs. 


Test 
perct. 


Milk 
lbs. 


Test 
per et. 


Milk 
lbs. 


Test 
per ct. 


Milk 
lbs. 


Test 
perct. 


•< 


No.] 

" 2.. 


3500 

700 

2480 


3.6 
3.8 
4.2 


3000 

665 

2000 


8.5 

3.8 
3.8 


3600 
720 
1850 


3.65 

3.6 

4.0 


3450 
750 
1500 


3.45 

3.7 

3.6 


13, 550 

2, 825 
7,830 


3.55 
3.73 
3.9 


" 3 





Multiplying each patron's total milk by his average test 
gives the number of pounds of butter fat in his milk, and 
this figure multiplied by .16^^ shows the money due for his 
milk, as given below. 
12 



178 



Testing Milk and Its Products. 



PATRON. 


Total milk 
lbs. 


Average test, 
per cent. 


Butter fat. 
lbs. 


Price of fat 
per lbs., cents 


Amounts 
due. 


No, 1 


13, 550 
2,825 
7,830 


3.55 

3.7 

3.9 


481.0 
104.5 
305. 4 




$78. 56 


" 2 


16.75 


" 3 


48.96 







215. b. When the proprietor of a creamery agrees to 
pay a certain price for 100 lbs. of 4 percent, milk, the 
receipts for butter sold and the price per pound of butter 
do not enter into the calculation of the amount due each 
patron for his milk; but the weight and the test of each 
patron's milk are just as important as before. If it is agreed 
to pay 66 cents per 100 lbs. of 4 percent milk (i. e. milk con- 
taining 4 percent of butter fat), the price of one pound of but- 
ter fat will be 66 -^ 4 = 16|- cents, and the amount due each 
patron is found by multiplying the total weight of butter 
fat in his milk by this price. To facilitate this calculation^ 
so-called RelativeValue Tables have been constructed, the use 
of which is explained in the following (221). 

216. c. If a creamery agrees to pay for butter fat, say 
1^ cents per pound below the average market price obtained 
for butter each month, the price of one pound of butter fat 
is found by averaging the market quotations and subtract- 
ing 1^ cents therefrom. If the four weekly market prices 
were 17^, 17, 16^ and 19 cents, the average of these would 
be 17^ cents, and this less 1^ cents gives 16 cents as the 
price per pound of fat to be paid to the patrons; this price 
is then used in calculating the dividend as in case of 
method I a. 



Patron 

No. 


Total milk 
lbs. 


Average test, 
per cent. 


Butter fat, 
lbs. 


Price of fat. 
per lb., cents. 


Amounts 
due. 


1 
2 
3 


13, 550 
2,825 
7,830 


3.55 

3.7 

3.9 


481.0 
104.5 
305.4 


16 
16 
16 


S76.96 
16.72 
48.86 



Calculating Dividends, 179 

217. II. If the creamery is owned by the farmers, the 
running expenses for a month are subtracted from the net 
returns received for the butter, and the amount left is 
divided by the total number of pounds of butter fat deliv- 
ered during the month, to get the price to be paid per pound 
of butter fat. This price is used for paying each patron for 
his milk according to the amount of fat contained therein, 
as already explained under Proprietary Creameries (214). 

The monthly running expenses of a co-operative creamery 
generally includes such items as the wages of the butter 
maker (and manager or secretary, if these officers are sal- 
aried), labor (hauling, helper, etc.), cost of butter packages, 
coal or wood, salt and other supplies, freight and commis- 
sion on the butter sold, repairs and insurance on buildings, 
etc. A certain amount is also paid into a sinking fund, 
which represents the depreciation of the property, wear and 
tear of building and machinery, bad debts, etc. These items 
are added together, and their sum subtracted from the gross 
receipts for the butter sold during the month. 

218. Assuming the receipts for the butter sold during 
the month to be $1197, and the running expenses of the 
factory $285, the amount to be divided among the patrons 
is $912, the quantity of butter fat received was 5700 lbs., 
and the price per pound of butter fat will therefore be 16 
cents. The account will then stand as follows: 



Patron 
No. 


Total milk 
lbs. 


Average test, 
per cent. 


Butter fat, 
lbs. 


Price per lb. of 
butter fat, cents 


Amounts 
due. 


1 

2 
3 


13, 5.50 

2,8iS 
7,830 


3.55 

3.7 

3.9 


481.0 
104.5 
305. 4 


16 

16 
16 


$76.96 
16.72 

48.86 



i8o Testing Milk and Its Products. 

219. Other systems of payment. Besides these four 
systems of payment, there are various other agreements 
made between manufacturer and producer, but with them 
all the one important computation of the price to be paid 
per pound of butter fat is the basis of calculating the factory 
dividends, when milk is paid for by the Babcock test. 

220. Paying for butter delivered. In some instances 
patrons desire to receive pay for the quantity of butter 
which the milk delivered by them will make. This can be 
ascertained quite accurately from the total receipts and the 
total weight of both butter fat and butter. The total money 
to be paid for butter (the net receipts) are divided by the 
number of pounds of butter sold, to get the price to be paid 
per pound of butter; the total yield of butter divided by 
the total amount of butter fat delivered in the milk, gives 
the amount of butter corresponding to one pound of butter 
fat, and the pounds of fat delivered by each patron is then 
multiplied by this figure. This method requires more figur- 
ing, than those given in the preceding, and the dividends 
are no more accurate, in fact, less so, than when calculations 
are based on the price per pound of fat. 

221. Relative value tables. These tables give many 
of the multiplications used in computing the amount due 
for various weights of milk testing from 3 to 6 per cent, of 
fat. They can be easily constructed by any one as soon as 
the price of one pound of fat is determined in each case. If 
the price to be paid per pound of fat is, say, 15 cents, the value 
of each 100 lbs. of milk of different quality is found by multi 
plying its test by 15. If the average tests of the different 
patrons' milk vary from 3 to 5 percent, the relative value 
table would be as follows: 



Calculating Dividends, i8i 



3.6 X 15 = 54c. per 100 lbs. 

3.7 X 15 = 55.5c. 

3.8 X 15 = 57c. 

3.9 X 15 = 58.5c. 
4.0X15 = 60c. 

etc. 



3.0 X 15 = 45c. per 100 lbs. 

3.1 X 15 = 46.5c. 

3.2 X 15 = 48c. 

3.3 X 15 = 49.5c. 

3.4 X 15 = 51c. 

3.5 X 15 = 52.5c. 

Continuing this multiplication, or adding the multiplier 
each time, in the same way for each tenth of a percent, up 
to 5 percent, of fat, gives a table that can be used for calcu- 
lating the amount due per 100 lbs. of milk, at this price per 
pound, and the weight of milk delivered by each patron is 
multiplied by the price per 100 lbs. of milk shown in the 
table opposite the figure representing his test. 

Example. A patron supplies 2470 lbs. of milk testing 3.2 per- 
cent of fat; price per pound of fat 15 cents; he should then receive 
24.70 X 48c. =$11. 85, (see above table). Another patron deliver- 
ing 3850 lbs. of milk testing 3.8 percent, will receive, at the same 
price per pound of fat, 38.50 X 57c. = $21.94. 

The relative value tables in the Appendix give the price 
per 100 lbs. of milk testing between 3 and 6 percent fat, 
when the price of three percent milk varies from 30 to 90c. 
per 100 lbs. In using the tables, first find the figure show- 
ing the price which it has been determined to pay for 100 lbs. 
of milk of a certain quality, say 3 or 4 percent milk; the 
figures in the same vertical column then give the price to be 
paid per 100 lbs. of milk testing between 3 and 6 percent. 

Example 1. It has been decided to pay 90 cents per 100 lbs. of 
4 percent milk. The figure 90 is then sought in the table in the 
same line as 4.00 percent, and the vertical column in which it is 
found, gives the price per 100 lbs. of 3 to 6 percent milk. 3.8 percent 
milk is thus worth 85 cents per 100 lbs., and 4.5 percent milk, 
$1.01, under the conditions given. The prices of other qualities of 
milk are found in the same way. 



l82 



Testing Milk and Its Products, 



Example 2. In the example referred to under Illustrations of 
Calculating Creamery Dividends (I b, 215), the figures for the 
patrons No. 1, 2, and 3, would be as follows: 



Patron No. 


Milk delivered 
lbs. 


Average test. 


Price per 100 lbs. 
of milk, cents. 


Amounts due. 


1 


13550 
2325 

7830 


3.55 

3.7 

3.9 


58.5 

61. 

64. 


$79.26 


2 


17.23 


3 


50.11 



B. — Calculating Dividends at Cheese Factories. 

222. The amount of cheese made from a certain quantity 
of milk depends, as before shown (206), in a large measure 
on the richness of the milk in butter fat. Rich milk will 
give more chesse per hundred weight than poor milk, and 
the increased yields will be nearl}', but not entirely, propor- 
tional to the fat contents of the different kinds of milk. 
Since the quality of the cheese produced from rich milk is 
better than that of cheese made from thin milk, and will de- 
mand a higher price, it follows that no injustice is done by 
rating the value of milk for cheese production by its fat 
content. This subject has been discussed frequently during 
late years in experiment station publications and in the 
dairy press (see 206). Among others, Babcock has shown 
that the price of cheese stands in a direct relation to its 
fat content.* Prof. Robertson, the Dairy Commissioner of 
Canada, is authority for the statement that the quality of 
the cheese made from milk containing 3.0 to 4.0 percent of 
fat was increased in value by one-eighth of a cent for every 
two-tenths of a percent of fat in the milk,t a figure which 
is fully corroborated by Dr. Babcock's results. The injustice 



* Wisconsin exp. station, 11th report, p. 134. 
t Hoard's Dairyman. March 29, 1895. 



Calculating Dividends. 183 

of the " pooling system," by which all kinds of milk receive 
the same price, is evident from the preceding; if the milk of 
a certain patron is richer than that of others, it will make a 
higher grade of cheese, and more of it, per hundred weight, 
and hence should be paid a higher price. 

Payment on the basis of the fat content of milk is, there- 
fore, the most equitable method of valuing milk for cheese 
making, and in case of patrons of cheese factories as with 
creamery patrons, dividends should be calculated from the 
results obtained by testing the milk delivered. The testing 
may be conveniently arranged by the method of composite 
sampling, in the same way as already described for cream- 
eries (162). 

223. Calculation of dividends. As with creameries 
the first thing to be ascertained is the price to be paid per 
pound of butter fat. The factory records should show the 
number of pounds of cheese made from the total milk de- 
livered to the factory during a certain time, generally one 
month, and the money received for this cheese. The cost of 
making cheese and all other expenses that should be paid 
for out of the money received for the cheese are deducted 
from the total receipts, and the difference is divided among 
the patrons in proportion to the amounts of butter fat de- 
livered in the milk. 

The weights of the milk delivered, and the tests of the 
composite samples furnish data for calculating the quantities 
of butter fat to be credited to each patron. The money to 
be paid to the patrons is then divided by the total weight of 
butter fat delivered to the factory, and the price of one 
pound of fat thus obtained. The money due each patron 
is now found by multiplying the total number of pounds of 
butter fat in his milk by this price per pound. 



184 Testing Milk and Its Products. 

The illustrations already given for calculating patrons' 
dividends at creameries according to the various methods, 
will serve equally well to show the manner in which divi- 
dends are calculated at a cheese factory. For the sake of 
clearness an example is given that applies directly to cheese 
factories. 

224, Illustrations of calculation of dividends. It 
may be assumed that 15,000 lbs. of green cheese is made 
from 150,000 lbs. of milk delivered to a factory in a month; 
according to the weighings and the tests made, the milk con- 
tained 5700 lbs. of butter fat. If the cheese sold at an 
average price of 7^ cents a pound, the gross receipts would 
be $1,125.00. The amount to be deducted from the gross 
receipts will depend on the agreement made between the 
factory operator and the patrons, in case of proprietary 
cheese factories, or between the shareholders and the maker, 
when the factory is run on the co-operative plan. As be- 
fore we shall consider these systems separately. 

225. I. Proprietary cheese factories. The owner of the 
factory generally agrees to make the cheese for a certain 
price per pound, and to pay the patrons what is left after 
deducting this conclusion. If the price agreed on is 1^ 
cents per pound of green cheese, this would amount to $225, 
in the example given. Subtracting this sum from the gross 
receipts, $1,125, leaves $900, which is to be paid the patrons. 
The total amount of butter delivered by the patrons was 
5700 lbs.: hence the price of one pound of butter fat will be 
900 -^5700 = .1577, or 15.8 cents. Taking the figures for 
the three patrons already mentioned under creamery divi- 
dends, we then have: 



Calculating Dividends. 



i8s 



Patron. 


Total milk, I Average test, 
lbs, percent. 


Butter fat. 
lbs. 


Price per 
lb. of fat. 


Amounts due. 


No. 1 

No. 2 

No. 3 


18, 5S0 

2,825 
7,830 


3.55 

3.7 

3.9 


481.0 
104.5 
305.4 


15.8c. 
15. 8c. 
15. 8c. 


$76. 00 
16.57 
48.25 



206. II. Co-operative cheese factories. The method of 
payment at co-operative cheese factories is nearly the same 
as that already given, except that a certain sum represent- 
ing the expenses is subtracted from the gross receipts for 
the cheese, and the balance is divided among the patrons 
according to the amounts of butter fat furnished b}^ each, in 
the same manner as in the above case, after the price of a 
pound of fat has been obtained. 

The price per 100 lbs. of milk can be calculated in the 
the same way as at creameries, by multiplying the test of 
each lot by the price per pound of fat. 



1 86 Testing Milk and Its Products. 



CHAPTER XIV. 

CHEMICAL ANALYSIS OF MILK AND ITS PRODUCTS 

227. An outline of the methods followed in determining 
quantitatively the components of milk and its products is 
given in the following, for the guidance of advanced dairy 
students. This work cannot be done outside of a fairly well- 
equipped chemical liboratory, or by persons who have not 
been accustomed to handling delicate chemical apparatus 
and glassware, analytical balances, etc., and who have not a 
knowledge of at least the elements of chemistry and chem- 
ical reactions. 

A. — Milk. 

208. In a complete milk analysis, the specific gravity of 
the milk is determined, and the following milk components, 
water, fat, casein and albumen, milk sugar, and ash. The 
methods of analysis described in the following are those 
used in the chemical laboratory of the Wisconsin experiment 
station, which in the main are the same as those adopted by 
the Association of Official Agricultural Chemists, and in use 
with but slight modifications in the chemical laboratories of 
all American experiment stations and schools.^ 

229. a. Specific gravity is determined by means of a 
picnometer or specific gravity bottle, since more accurate 



* The methods of analysis adopted by the Asso. of OflScial Agr'l Chemists are 
published annually by the chemical division of the U. S. Department of Agricul- 
ture; see Bull. No. 46, Washington, 1895, edited by Harvey W. Wiley, secretary, 
pp. 84. 



Chemical Analysis of Milk and Its Products. 187 

results will thus be reached than by usmg an ordinary 
Quevenne lactometer. A thermometer is ground into the 
neck of the specific gravity bottle so as to form a stopper, 
and the bottle is provided with a glass-stoppered side tube 
to furnish an exit for liquids on expanding. A specific 
gravity bottle holding 100 grams of water is preferably used. 
The empty and scrupulously cleaned bottle is first weighed 
on a chemical balance. The bottle is then filled with re- 
cently-boiled distilled water of a temperature below 60° F. 
(15.5° C); the thermometer is inserted, and the bottle is 
warmed slightly by immersing it for a moment in tepid water 
and left standing until the thermometer shows G0° F.; the 
opening of the. side tube is then wiped oflT and closed with 
the stopper, and the water on the outside of the bottle and 
in the groove between its neck and the thermometer wiped 
ofl" with filter paper or a clean handkerchief, when the bottle 
is again weighed. The weight being recorded, the bottle is 
emptied and dried in a water oven, or, if sufficient milk is at 
hand, the bottle is repeatedly rinsed with the milk, the spe- 
cific gravity of which is to be determined. It is then filled 
with milk in a similar manner as in case of water; the tem- 
perature of the milk should be slightly below 60° F., and is 
gradually brought up to this degree after the bottle has 
been filled, proceeding in the same manner as before with 
water; the weight of the bottle and milk is then taken. 

The weights of water and of milk contained in the specific 
gravity bottle are found by subtracting the weight of the 
the empty bottle from the second and third weight, respec- 
tively, and the specific gravity of the milk then found by 
dividing the weight of the milk by that of the water. 



1 88 Testingr Milk and Its Products. 



%s» 



Example: Weight of sp. gr. bottle + water. ,.146. 9113 grams. 
Weight of sp. gr. bottle empty 46.9423 " 

Weight of water 99.9690 grams. 

We'ght of sp. gr, bottle + milk 149.8718 grams. 

Weight of sp. gr. bottle empty 46.9423 " 

Weight of milk 102.9285 grams. 

^ ' . .„ 102.9285 . ..one 

Sp.gr. of mdk= ^^^3^ =1-0296 

230. If a plain picnometer without a thermometer at- 
tached, is available, the method of procedure is similar to that 
described, with the difference that the temperature of the 
water and of the milk must be brought to 60° F., before the 
picnometer is filled, or the picnometer filled with either liquid 
is placed in water in a small beaker, which is very slowly 
warmed to 60° F. and kept at this temperature for some 
time so as to allow the liquid in the picnometer to reach the 
temperature desired; the temperature of the water in the 
beaker is ascertained by means of an accurate chemical 
thermometer. The perforated stopper is then wiped off, the 
picnometer is taken out of the water, wiped and weighed. 
It is necessary to weigh very quickly if the room temper- 
ature is much above 60° F., as in such cases the expanding 
liquid will flow on to the balance pan, with a resultant loss 
in weight from evaporation. 

The weights of specific gravity bottle or picnometer, 
empty and filled with water, need only be determined a 
couple of times, and the averages of these weighings used in 
subsequent determinations. 

231. b. Water. The milk is weighed into a perforated 
copper tube filled with prepared dry asbestos. The tubes 
are made from perforated sheet copper, with holes about 



Chemical Analysis of Milk and Its Products. 189 

.7 mm. in diameter and about .7 mm. apart; they are 60 mm. 
long, 20 mm. in diameter and closed at the bottom. The 
asbestos is prepared from clean fibrous asbestos, which is 
ignited in a muffle oven, treated with dilute HCl (1 : 3) and 
then with distilled water till all acid is washed out; it is then 
torn in loose layers and dried at a low temperature in an air 
bath; when dry it can be easily shredded in fine strings and 
is placed in a wide-mouth, glass-stoppered bottle. 

About 2 grams of asbestos are placed in each tube, pack- 
ing it rather loosely; the tube is then weighed, a small narrow 
beaker being inverted over it on the scale pan. 5 cc. of milk 
are then dropped on to the asbestos from a 5 cc. fixed pipette, 
the beaker again placed over the tube, and the weight of 
the 5 cc. of milk delivered + copper tube taken. The weight 
of the milk is obtained by difference. The tubes are now 
placed in a steam oven and heated to 100° C. until they no 
longer decrease in weight, which ordinarily will take about 
three hours. Place in dessiccator until cold, and weigh; the 
difference between the weight of the tube + milk and this 
last weight gives the water contained in the milk, which is 
then calculated in percent of the quantity of milk weighed 
out. 

Example. Weight of tube + breaker + milk 29.3004 grams. 

Weight of tube + beaker 24..1772 



Milk weighed out 5.1232 grams. 

Weight of tube + beaker + milk 29.3004 grams. 

Weight oftube + beaker + milk, dry. .24. 9257 " 



Weight of water 4.3747 grams. 

Percent of water in milk = ^-^^^^XlOO ^ gg 39 ppj-cent. 

5.1232 ^ 

Note. The percent of total solids in milk is often given, 
instead of that of water; this may be readily obtained by 



ipo Testing Milk and Its Products. 

subtracting the weight of the empty tube from that of the 
tube filled with milk solids, and finding the percent of the 
milk weighed out which this difference makes. In the 
above example, the weight of milk solids thus is 24.9257 — 
24.1772 = .7485 grams, and the percent, of total in the milk 
= 14.61 percent. 

232. Alternate method. 5 cc of milk are measured out 
on a weighed flat porcellain dish (50-60 mm. in diameter; 
porcellaiu crucible covers will answer the purpose better 
than any other vessel on the market, provided the handle 
be broken off or ground off level on an emory wheel); this 
is weighed rapidly; two or three drops of 30 percent acetic 
acid are added, and the dish is dried in a steam oven at 100° C 
until no further loss in weight is obtained. After cooling in 
desiccator, the weight of the milk solids is obtained, and by 
calculation as before, the percent of water or total solids in 
the milk. 

233. c. Fat. The dried tubes from the water deter- 
mination are placed in Caldwell extractors and connected 
with weighed, numbered glass flasks (capacity, 2-3 oz); the 
extractors are attached to upright Liebig condensers and 
the tubes extracted with pure ether, free from water, alco- 
hol or acid, until all fat is dissolved; 4-5 hours' extraction 
is suflficient; in case of samples of skim milk it is well to 
continue the extraction for 6 hours. The ether is then dis- 
tilled off and recovered, and the flasks dried in a copper 
oven until constant weight; after cooling they are weighed, 
and the amount of fat contained in the quantity of milk 
originally weighed into the tubes is thus ascertained, and 
the percent, present in the milk calculated. 



Chemical Analysis of Milk and Its Products. 191 

Example: Weight of flask + fat 15.8039 grams. 

Weight of flask 15.5171 

Weight of fat 2868 grams. 

Milk weighed out 5.1232 grams. 

Per cent, of fat in milk = -2868 X 10 ^ 5 53 percent. 

5.1232 

234. Casein and albumen. The sum of these com- 
ponents is generally determined by the Kjeldahl method.* 
5 cc. of milk are measured carefully into a flat-bottom 800 
cc. Jena flask, 20 cc. of concentrated sulfuric acid (C. P., sp. 
gr., 1.84) are added, and .7 gram of mercuric oxid (or its 
equivalent in metallic mercury); the mixture is then heated 
over direct flame until it is straw colored or perfectly white; 
a few crystals of potassium permanganate are now added 
till the color of the liquid remains green. All the nitrogen 
in the milk has now been converted into the form of am- 
monium sulfate. iVfter cooling, 200 cc. of distilled water, 
free from ammonia, are added, 20 cc. of a solution of pot- 
assium sulfid (containing 40 grams sulfid per liter), and a 
fraction of a gram of powdered zink. A small quantity of 
semi-normal HCl solution, more than suflScient to neutralize 
the ammonia obtained in the oxidation of the milk, is now 
carefully measured out from a delicate burette (divided in 
^ cc.) into an Erlenmeyer flask, and the flask connected 
with a distillation apparatus. At the other end, the Jena 
flask containing the watery solution of the ammonium sul- 
fiate is connected, after adding 50 cc. of a concentrated soda 
solution (1 pound " pure potash " dissolved in 500 cc. of 
distilled water, and allowed to settle); the contents of the 
Jena flasks are now heated to boiling, and the distillation is 

* Fresenius' Zeitschrift, p. 22, 366; U. S. Dept. Agr., Chem. Div., bull. 43. 



192 Testing Milk and Its Products. 

continued for 40 minutes to an hour, until all the ammonia 
has been distilled over. 

The excess of acid in the Erlenmeyer receiving flask is 
then accurately titrated back by means of a tenth-normal 
standard ammonia solution, using a cochineal solution* as 
an indicator. From the amount of acid used, the percent 
of nitrogen, and from it, the percent of casein and albumen 
in the milk is obtained by multiplying by 6.25.t The 
amount of nitrogen contained in the chemicals used is 
determined b}^ blank experiments, and deducted from the 
nitrogen obtained as described. 

Example: The weight of 5 cc. of milk (as obtained in deter- 
mining the water in milk, see a.) was 5,1465 grams. 5 cc. of 

N 
standard HCl are added in the receiver, and 1.55 cc. of— alkali 

solution are used in titrating back the excess of acid. 1.55 cc. of 

T— alkali = -'_ = .51 cc. - acid solution; the ammonia distilled 
10^ 5 J 

over therefore neutralized 5 — .51 = 4.49 cc. acid. By blank trials 
it was found that the reagents used furnish an equivalent of 
.02 cc. acid in the distillate; this quantity subtracted from the 
acid-equivalent of the nitrogen of the milk leaves 4.47 cc. 1 cc. 
semi-normal HCl. solution corresponds to 7 milligrams or .007 

N 
grams of nitrogen; 4.47 cc. — HCl. therefore represents .03129 

grams of nitrogen. This quantity of nitrogen was obtained irom 
the 5.1465 grams of milk measured out; the milk therefore con- 
tains ^^^^^^1:^^^ = .608 percent of nitrogen, and .608 X 6.25 
5.1465 

= 3.80 percent of casein and albumen. 

235. Casein and albumen may be determined separately 
by Van Slyke's method: J 10 grams of milk are weighed out 

* Sutton, Volumetric Analysis, 4th edition, p. 31. 

t The factor 6.30 or 6.37 is more correct for the albumenoids of milk, but has 
not yet been generally adopted. 

t Bulletin No. 43, p. 189, Chem. Division, U. S. Dept. of Agriculture. 



Chemical Analysis of Milk and Its Products. 193 

and diluted with about 90 cc. of water at 40°-42° C. 15 cc. 
of a 10 percent acetic acid solution are then added; the 
mixture is well stirred with a glass rod and the precipitate 
allowed to settle for 3-5 minutes. The whey is decanted 
through a filter and the precipitate washed two or three 
times with cold water. The nitrogen is determined in the 
filter paper and its contents by the Kjeldahl method; blank 
determinations with the regular quantities of chemicals and 
the filter paper used are made, and the nitrogen found 
therein deducted. The percent of nitrogen obtained multi- 
plied by 6.25 gives the percent of casein in the milk. 

236. Albumen is determined in the filtrate from the 
casein precipitate; the filtrate is placed on a water bath and 
heated to boiling temperature of water for ten to fifteen 
minutes. The washed precipitate is then treated by the 
Kjeldahl method for the determination of nitrogen; the 
amount of nitrogen multiplied by 6.25 gives the amount of 
albumen in the milk. The diff'erence between the total 
nitrogenous components found by the Kjeldahl method, and 
the sum of the casein and the albumen, as given above, is 
due to the presence in milk of a third class of nitrogen 
compounds, called by various authors, globulin, lactopepton, 
nuclein, etc. (18). 

237. e. Milk sugar is generally determined by difl^erence, 
the sum of fat, casein and albumen (total N x 6.25), and 
ash, being subtracted from the total solids. It may be de- 
termined directly by means of a polariscope, or gravimetric- 
ally by Fehling's solution; only the former method, as 
worked out by "Wiley, ^ will be given here. 

The specific gravity of the milk is accurately determined, 
and the following quantities of milk are measured out by 

* Agricultural Analysis, iii, p. 275; Am. Chem. Jour., 6, p. 289 et seq. 
13 



194 Testing Milk mid Its Products. 

means of a 100 cc. pipette graduated to .2 cc. (or a 64 cc. 
pipette made especially for this purpose, with marks on the 
stem between 63.7 and 64.3 cc), according to the specific 
gravities given: 1.026, 64.3 cc; 1.028, 64.15 cc; 1.030, 64.0 
cc; 1.032, 63.9 cc; 1.034, 63.8 cc; 1.036, 63.7 cc These quan- 
tities refer to the Soleil-Ventzke half-shadow poiariscopes, re- 
quiring a normal weight of 26.048 grams of sugar. The milk 
is measured into a small flask graduated at 100 cc. and 102.6 
cc; 30 cc of mercuric iodid solution (prepared from 33.2 
grams potassium iodid, 13.5 grams mercuric chlorid, 20 cc 
glacial acetic acid and 640 cc water) are added; the flask is 
fllled to 102.6 cc. mark with distilled water, the contents 
mixed, flltered through a dry filter, and when the filtrate is 
perfectly clear, the solution is polarized in a 200 millimeter 
tube. The readings of the scale divided by 2 shows the per- 
cent of lactose (milk sugar) in the milk. Take five readings 
of two different portions of the filtrate, and average the 
results. 

238. f. Ash. About 20 cc. of milk are measured into 
a flat bottom porcellain dish and weighed; about one-half of 
a cc of 30 percent acetic acid is added, and the milk first 
dried on water bath, and then ignited in a muflle oven at a 
low red heat. Direct heat should not be applied in deter- 
mining the ash of milk, since alkali chlorids are likely to be 
lost at the temperature to which milk solids have to be 
heated to ignite all organic carbon. 

Example. Weight of porcellain dish + milk 49.0907 grams.. 

Weight of porcellain dish 28.3538 

Weight of milk 20.7369 grams. 

Weight of dish + milk, after ignition.. 28. 5037 grams. 
Weight of dish 28.3538 

Weight of milk ash 1499 grams. 

Percent of ash = -^^^^XlOO ^ ^^ percent. 
20.7369 



Chemical Analysis of Milk and Its Products. 195 

239. Acidity of milk. The acidity of milk is con- 
veniently determined by means of Farrington's alkaline 
tablets (see p. 99), or by one-tenth normal soda solution. In 
the latter case, 20 cc. of milk are measured into a porcellain 
casserole; a few drops of an alcoholic phenolphtalein solu- 
tion are added, and soda solution is dropped in slowly from 
a burette until the color of the milk remains uniformly 

pinkish on agitation. 1 cc. of — alkali corresponds to .009 
grams lactic acid, or to .045 percent, when 20 cc. of milk are 
taken, (see p. 98). 

Detection of Pretervatives in Milk. 

240. a. Boracic acid (borax^ borates, preservaline, etc.) 
100 cc of milk are made alkaline with a soda or potash 
solution, evaporated to dryness and incinerated. The ash 
is dissolved in water to which a little hydrochloric acid has 
been added, and the solution filtered. A strip of turmeric 
paper moistened with the filtrate will be colored reddish 
brown when dried at 100° C on a watch glass. 

If a little alcohol is poured over the ash to which cone, 
sulfuric acid has been added, and fire is set to the alcohol 
alter a little while, it will burn with a yellowish green tint, 
especially noticeable if the ash is stirred with a glass rod 
and when the flame is about to go out. 

241. The following modification of the first test given is 
said to prove the presence of onl}' a thousandth of a gram 
of borax in a drop of milk* (.13 percent.): Place in a 
porcellain dish one drop of milk with two drops of strong 
hydrochloric acid and two drops of saturated turmeric tinct- 
ure; dry this on the water bath, cool and add a drop of am- 

* N. J. Dairy commissioner, report 1896, p. 37. 



196 Testing Milk and Its Products. 

monia by means of a glass rod. A slaty blue color, chang- 
ing to green, is produced if borax is present.* 

242. b. Bi=Carbonate of soda. 100 cc. of milk to 
which a few drops of alcohol are added, are evaporated and 
carefully incinerated; the proportion of carbonic acid in the 
ash, as compared with that of milk of known purity, is de- 
termined. If an apparatus for the determination of carbonic 
acid is available, like the Scheibler apparatus, etc., the per- 
cent, of carbonic acid per gram of ash (and quart of milk) 
can be easily determined. Normal milk ash contains only a 
small amount of carbonic acid (less than 2 per cent), pre- 
sumably formed from the citric acid of the milk in the pro- 
cess of incineration. 

The following quantitative test is easily made: To 10 cc. 
of milk add 10 cc. of alcohol and a little of a one-percent 
rosolic acid solution. Pure milk will give a brownish yellow 
color; milk to which soda has been added, a rose red color. 
A control experiment with milk of known purity should be 
made. 

243. c. Fluorids. 100 cc. of milk are evaporated in 
a platinum or lead crucible, and incinerated; the ash is 
made strongly acid with cone, sulfuric acid. If fluorids are 
present, hydrofluoric acid will be generated on gentle heat- 
ing, and will be apparent from its etching a watch glass 
placed over the crucible. 

244. d. Salicylic acid {salicylates, etc.). 20 cc. of milk 
are acidulated with sulfuric acid and shaken with ether; the 
ether solution is evaporated, and the residue treated with 
alcohol and a little iron chlorid solution; a deep violet color 
will be obtained in the presence of salicylic acid. 



* See also 132, 137, 



Chemical Analysis of Milk and Its Products. 197 

245. e. Formaline (a fortj^-percent solution of formal- 
dehyde in water). A solution of diphenylamin is made with 
water and just enough sulfuric acid to secure a proper sol- 
vent effect. The milk to be tested, or better, the distillate 
therefrom, is added to this solution and boiled. If formaline 
be present, a white flocculent precipitate is formed; if the 
acid used contained nitrates, a green precipitate will be 
formed.* 

B. — Skim-jiilk, Butter-milk, Whey. 

246. The analysis of these products is conducted in the 
same manner as in case of whole milk, and the same con- 
stituents are determined, when a complete analysis is wanted. 
As they generall}^ contain only small quantities of solids, 
and especially of fat, it is well to weigh out a larger quan- 
tity than in case of whole milk; if possible, toward 10 grams. 
The acidity of some milk and butter milk must be neutral- 
ized with sodium carbonate previous to the dr3'ing and ex- 
traction, as lactic acid is soluble in ether and would thus 
tend to increase the ether-extract (fat) if not combined with 
an alkali previous to the extraction. 

C. — Butter. 

248. Sampling. A four to eight-ounce sample of but- 
ter is melted in a tightly closed fruit jar, shaken vigorously 
and cooled until the butter is hardened, the jar being shaken 
at short intervals during the cooling so as to keep the water 
of the butter evenl}^ distributed in the mass. 

249. a. Determination of water. Small pieces of 
butter (about 2 grams in all) are taken from the sample by 
means of a steel spatula, and placed in glass tubes, seven- 



* See also Chem. News, 1893, No. 71; Milchzeitung, 1896, 491; 1897, 40, 667. 



1 98 Testing Milk and Its Products. 

eighths of an inch in diameter and two and a half inches 
long, closed at the bottom by a layer of stringy asbestos, 
and filled two -thirds full of asbestos prepared as for milk 
analysis (231). The tubes are dried at 100° C. in the water 
oven, until no further loss in weight takes place, and are 
then cooled and weighed. The percent of water is deter- 
mined as in case of milk analyses. 

250. b. Fat. The tubes are placed in Caldwell's ex- 
tractors and extracted for four hours with anhydrous ether; 
the ether is then distilled off, and the flasks dried in the 
steam bath and weighed, the increase in weight being the 
fat in the samples of butter weighed out. 

251. c. Casein. 10 grams of butter are weighed into a 
small beaker provided with a lip, and treated twice with 
about 50 cc. of gasoline each time; the solution is filtered 
ofl, and the residue transferred to a filter and dried; its ni- 
trogen content is then determined by the Kjeldahl method 
(284). The nitrogen in the filter and chemicals used is deter- 
mined by blank trials and deducted. The nitrogen multi- 
plied by 6.25 gives the casein in the butter. 

252. d. Ash. 1. 10 grams of butter are weighed into 
a porcellain dish and treated twice with gasoline, as in pre- 
ceding determination, the solution is filtered through an 
ash-free (quantitative) filter, and the filter when dry, is 
transferred to the dish. The dish is heated in an air-bath 
for half an hour and then placed in a muffle oven, where the 
contents are burnt to a light greyish ash; the dish is now 
cooled in a desiccator and weighed. The diflerence between 
this weight and that of the empty dish gives the amount of 
ash in the butter weighed out. 



Cheinical Analysis of Milk and Its P?'oducts. 199 

253. 2. About 2 grams of butter are weighed into a 
small porcellain dish, half filled with stringy asbestos; the 
dish is dried for an hour in the water oven, and the fat then 
set fire to with a match, the asbestos fiber serving as a wick. 
When the flame has gone out, the dish is placed in a muffle 
oven, and the residue burnt to a greyish ash. After cool- 
ing, the dish is weighed, and the percent, of ash in the butter 
calculated as under method a. 

254. Complete analysis of butter in the same 
sample. About 2 grams of the butter are weighed into a 
platinum gooch, half filled with stringy asbestos, and dried 
in water oven at 100° C. to constant weight, cooled and 
weighed. The difference gives water in the sample. The 
gooch is then treated repeatedly -with small portions of 
gasoline, suction being applied, and again dried in the water 
oven, cooled, and weighed; the fat in the sample is obtained 
from the difference between this and the preceding weight. 
The gooch is then carefully heated over direct flame until a 
light greyish ash is obtained; this operation is preferably 
done in a muffle oven to avoid possible loss of alkali chlo- 
rids. The loss in weight gives the casein in the sample 
weighed out, and the increase in the weight of the gooch 
over that of the empty gooch with asbestos gives the ash 
(mainly salt) of the butter. The salt in the ash may be dis- 
solved out by hot water, acidulated with a drop or two of 
nitric acid, and the chlorin content of the solution deter- 
mined by means of a standard silver nitrate solution using 
potassium chromate as an indicator. 



200 Testing Milk and Its Products. 

Detection of Artificial Butter. 

255. Determination of the specific gravity of the filtered 
butter fat serves as a good preliminary test. A number of 
practical methods for the detection of artificial butter have 
been proposed, but they are either worthless, in case of sam- 
ples containing a considerable proportion of natural butter, 
or give satisfactory results only in the hands of experts. 
The Reichert-Wollny method given in detail below is the 
standard method the world over, and the results obtained 
by it are accepted in the courts. 

256. Filtering the butter fat. The butter to be ex- 
amined is placed in a small narrow beaker and kept at 60° C. 
for about two hours. The clear supernatant fat is then filtered 
through absorbent cotton into a 200 cc. Erlenmeyer flask, 
taking care that none of the milky lower portion of the 
contents of the beaker be poured on the filter. In sampling 
the butter fat, it is poured back and forth repeatedly from 
a small warm beaker into the flask, and the quantity wanted 
is then drawn ofl with a warm pipette. 

257. Specific gravity. This is generally determined 
at 100° C. The method of procedure is similar to that de- 
scribed under milk (230). The picnometer (capacity about 
25 cc.) filled with dry filtered butter fat, free from air bubbles; 
the fat is heated for 30 minutes in a beaker, the water in 
which is kept boiling. On cooling, the weight of picnometer 
and fat is obtained, and by calculation as usual, the specific 
gravity of the fat. 

The specific gravity of pure natural butter fat at 100° C. 
ranges between .8650 and .8685, while artificial butter fat 
(i. e. fat from other sources than cows' milk) has a specific 
gravity at 100° C. of below .8610, and generally about .85. 



Chemical Analysis of Alilk and Its Products. 201 

258. Reichert=WoiIny method (FoZa^i7cJcicZs). 5.75 cc. 
of fat are measured into a strong 250 cc. weighed saponi- 
fication flask, by means of a pipette marked to deliver- 
this amount, and the flask when cool, is weighed again. 10 
cc. of 95 percent, alcohol and 2 cc. of a concentrated soda 
solution (1:1) are then added to the flask which is securely 
stoppered with a cork stopper tied down with a piece of 
twine. The flask is heated for an hour on the water bath, 
being gently rotated from time to time in order to facilitate 
the saponification. The flask is then uncorked, the alcohol 
evaporated slowly and the heating continued until the last 
traces of alcohol are gone. 

100 cc. of recently-boiled, distilled water are now added, 
and the flask heated on the water bath until the soap formed 
is completely dissolved, When cooled to about 70° C, 40 cc. 
of dilute sulfuric acid (25 cc. cone. H., SO4 per liter) are 
added to the soap solution to decompose the soap into free 
fatty acids and glycerol. The flask is restoppered and 
heated until the insoluble fatty acids separated out form a 
clear oily laj^er on the surface of the acid solution of the 
flask. After cooling to room temperature, a few pieces of 
pumice stone (prepared by throwing the pieces at a white 
heat into distilled water and keeping them under water until 
used) are added, the flask connected with a glass condenser, 
heated slowly till boiling begins, and the contents then dis- 
tilled at such a rate as will bring 110 cc. of the distillate 
over in as nearly thirty minutes as possible. 

The distillate is mixed thoroughly and filtered through a 
dry filter; 100 cc. of the filtrate are poured into a 250 cc. 
beaker and titrated with a deci-normal barium hydrate solu- 
tion, half a cubic centimeter of phenolphtalein solution 
being used as an indicator. A blank test is made in the 



202 Testing Milk and Its Products, 

same manner as described, and the alkali solution required 
deducted from the results obtained with the samples 
analyzed. The number of cubic centimeters of barium 
hydrate solution used is increased by one-tenth, and the so- 
called Relchert number thus obtained. 

The Reichert number for pure butter fat will ordinarily 
come above 24 cc; butter fat from strippers will have a low 
Reichert number. Pure oleomargarine will have a Reichert 
number of 1-2 cc; and mixtures of artificial and natural 
butters will show intermediate numbers. 

D. — Cheese. 
For method of sampling, see p. 78. 

259. a. Water. Five grams of cheese cut into very 
thin slices are weighed into a small porcellain dish filled 
about one-third full with freshly-ignited stringy asbestos; 
the dish is placed in a water oven and heated for ten hours. 
The loss in weight is taken to represent water. 

260. b. Fat. About 5 grams of cheese are ground finely 
in a small porcellain mortar with about twice its weight of 
anhydrous copper sulfate, until the mixture is of a uniform, 
light blue color and the cheese evenly distributed through- 
out the mass. The mixture is transferred to a glass tube, 
of the kind used in butter analysis (249), only a larger size; 
a little copper sulfate is placed at the bottom of the tube, 
then the mixture containing the cheese, and on top of it, a 
little extracted absorbent cotton or ignited, stringy asbestos; 
the tube is placed in an extraction apparatus and extracted 
with anhydrous ether for 15 hours. The ether is then dis- 
tilled off, the flasks dried in a water oven at 100° C, to con- 
stant weight, cooled and weighed. The method is apt to 



Chemical Analysis of Milk and Its Products. 203 

give too low results and, therefore, not to be preferred to the 
Babcock test for cheese (91). 

261. c. Casein (total nitrogen x 6.25). About 2 grams 
of cheese are weighed out on a watch glass and transferred 
to a Jena nitrogen flask, and the nitrogen in the sample de- 
termined according to the Kjeldahl method; the percentage 
of nitrogen multiplied by 6.25 gives the total nitrogenous 
components of the cheese. 

262. d. Ash. The residue from the water determina- 
tion is taken for the ash; it is preferably set fire to, in the 
same manner as explained under determination of ash in 
butter (253), before it is placed in the muffle oven and in- 
cinerated. The increase in the weight above that of the 
empty dish + asbestos, gives the amount of ash in the sam- 
ple weighed out. 

268. e. Other constituents. The sum of the percent- 
ages of water, fat, casein and ash, subtracted from 100 will 
give the percent, of other constituents, organic acids, milk 
sugar, etc., in the cheese. 

Detection of Oleomargarine Cheese (" Filled " 
Cheese) 

20 grams of cheese are extracted with ether in a Caldwell 
extractor or a paper extraction cartridge; the ether is dis- 
tilled off, and the fat dried in the water oven until there is 
no further loss in weight. 5.75 cc. of the clear fat are then 
measured into a 250 cc. saponification flask and treated ac- 
cording to the Reichert-Wollny method, as already ex- 
plained under Detection of Artificial Butter (255). 



APPENDIX. 



Table I. Composition of milk and its products. 



Cows' milk. 



Colostrum milk 

Cream 

Cream, Cooley. 
Skim milk, 

(gravity) 

Skim milk, 

(gravity) 

Skim milk, 

(centrifugal) 
Butter milk.... 



No. of 
analyses 



793 



Whey 



Cond' used milk 

(no sugar).... 

Condensed milk 

(sugar added) 

Butter 

sweet cream 
sour cream.. 

unsalted 

World 'sFair 

American 

premium... 

Cheese, cream.. 

" full cream. 

" Cheddar, 

green 

" Cheddar, 

cured 

" Worl'sFair 

mammoth 

" half skim.. 

'* skim 

" centrifugal 
skim 



900 

2173 

120,540 

42 

43 

203 

56 

354 



Water 



36 



302 
10 
11 
78 

350 

9 

27 

143 



pr. ct 

87.17 

87.75 

87.40 

86.48 

87.1 

74.57 

68.82 

73.90 

90.43 

90.52 

90.60 
90.12 
91.67 
93.38 
93.12 

58.99 

25.61 
13.59 
12.93 
13.08 
13.73 
11.57 

10.23 
36.33 
38.00 

36.84 

34.38 

32.06 
39.79 
46.00 

50.5 



Fat. 



pr. ct. 

3.69 
3.40 
3.75 
4.20 
4.1 
3.59 
22.66 
17.60 



Casein 

and 
alb'raen 



pr. ct. 



17.64t 
3.7 



.87 3.26 
32 



.31 
.09 

.27 
.32 

.27 

12.42 

10.35 
84.39 
84.53 

84.26 
84.82 
84.70 

85.74 
40.71 
30.25 

33.83 

32.71 

d4.43 
23.92 
11.65 

1.2 



3.06 
4.03 



.81 

11.92 

11.79 
.74 
.61 

.81 

1.; 



Milk 
sugar. 



pr. ct. 
4. 
4.60 
5.10 



2.67 
4.23 



4.74 



5.29 
4.04 



Ash. 



pr. ct 

.71 

.75 
.65 

i .71 



Authority. 



.56 
.63 
.62 

.70 



4.79 .65 
5.80 



14.49 

50.06 

,50 
,68 
66 



.95 

.96 
18.84 1.02 
25.35 1.43 



23.72 

26.38 

28.00 
29.67 
34.06 

43.1 



2.18 



2.1 

.66 
1.25 
1.19 

.09 

2.78 



3.05 
3.10 
4.97 



5.61 

2.95| 3.58 



5.51 



1.79 
3.42 



4.73 

4.87 

5.2 



Koenig.§ 
Fleischmann. 
Van Slyke. 
Holland. II 
Vieth. 
Koenig.§ 

Holland. II 

Koemg.§ 

Holland. II 

Koenig.§ 

Holland. II 
Koenig.§ 
Van Slyke. 

Koemg.§ 



Farrington. 

Morrow. 
Koenig.§ 



Van Slyke. 

Drew. 

Shutt. 
Koenig.§ 



Storch. 



42 analyses, f 8 analyses. + 13.60 percent albumen. 
Mostly European samples. |( Massachusetts samples. 



206 



Testing Milk and Its Products, 



Table II. Milk standards. 



Maine 

New Hampshire 

Vermont 

in May and June. 
Massachusetts 

in May and June. 

skimmed milk 

Rhode Island 

New York 

New Jersey.. 

Pennsylvania* 

District of Columbia. 

Georgia 

South Carolina 

Ohio 

Michigan* 

Wisconsin 

Minnesotat 

Iowa 

Oregont 

"Washington 

City of Chicago 

St. Louis 



Omaha 



cream, 



Denver. 



England.. 
Germany ' 



Solids. 



12.0 
13.0 
12.5 
12.0 
13.0 
12.0 



12.0 
12.0 
12.0 
12.5 
12.0 
12.0 
11.5 
12.5 
12.5 



13.0 



12.5 



12.0 
12.0 
22.0 
12.0 



12.0 
[11.5] 



Fat. 



Percent. 
3.0 



[3.25] 
3.0 
[3.7] 



2.5 

3.0 



3.0 
3.0 
3.5 
3.0 
3.0 
3.0 
3.0 
3.5 
3.0 
3.2 
3.0 
3.0 
2.8 

12.0 
3.0 

16.0 



2.5 
2.7 



* Specific gravity, 1.029 — 1.033 at 60° F. 

•f Cheese, 40 percent fat in solids. 

% Butter, 14 percent, water. 

I Specific gravity, 1.029 at 15° C. 



Solids not 
fat. 



Percent. 
[9.0] 



9.25 

[9.0] 

9.3 



9.3 
[9.5] 
[9.0] 



[9.51 


9.0 


[8.5] 
[8.5] 


[9.5] 


[9.5] 



[9.5] 
'[9".3]' 



[9.0 
[9.2 
[10.0 
[9.0] 



9.0 



Law or 
Ordinance of 



1893,255 
1883 

1888,108 

1886,318 
1885,252 

1893.338 

1882,82 
1885,106 



1889,86 

1889,219 

1889,425 

1889,247 

1892,50 

1893 

1892 

1887 
1893 

1893 



Appendix. 



207 



Table III. Quevenne lactometer degrees correspond= 
ing to N. Y. Board of Health lactometer degrees. 

(See p. 83). 



Bd. of Health 


Quevenne 


Bd. of Health 


Quevenne 


Bd. of Health 


Quevenne 


degrees. 


scale. 


j degrees. 


scale. 


degrees. 


scale. 


60 


17.4 


81 


23.5 


101 


29.3 


61 


17.7 


82 


23.8 


102 


29.6 


62 


18.0 


83 


24.1 


103 


29.9 


63 


18.3 


84 


24:4 


104 


30.2 


64 


18.6 


85 


26.6 


105 


30.5 


65 


18.8 


86 


24.9 


106 


30.7 


66 


19.1 


87 


25.2 


107 


31.0 


67 


19.4 


88 


25.5 


108 


31.3 


68 


19.7 


89 


25.8 


109 


31.6 


69 


20.0 


90 


26.1 


no 


31.9 


70 


29.3 


91 


26.4 


111 


32.2 


71 


20.6 


92 


26.7 


112 


32.5 


72 


20.9 


93 


27.0 


113 


32.8- 


73 


2]. 2 


94 


27.3 


114 


33.1 


74 


21.5 


95 


27.6 


115 


33.4 


75 


21.7 


96 


27.8 


116 


33.6 


76 


22.0 


97 


28.1 


117 


33.9 


77 


22.3 


98 


28.4 


118 


34.2 


78 


22.6 


99 


28.7 


119 


34.5 


79 


22.9 


100 


29.0 


120 


34.8 


80 


23.2 











208 



Testino" Milk and Its Products. 



Table IV. Correction table for specific gravity of milk. 





Temperature of milk (in degrees Fahrenheit). 




51 


52 


53 


54 


55 


56 


57 


58 


59 


60 


20 


19.3 


19.4 


19.4 


19.5 


19.6 


19.7 


19.8 


19.9 


19.9 


20.0 


21 


20.3 


20.3 


20.4 


20.5 


20.6 


20.7 


20.8 


20.9 


20.9 


21.0 


22 


21.3 


21.3 


21.4 


21.5 


21.6 


21.7 


21.8 


21.9 


21.9 


22 


23 


22.3 


22.3 


22.4 


22.5 


22.6 


22.7 


22.8 


22.8 


22.9 


23.0 


24 


23.3 


23.3 


23.4 


23.5 


23.6 


23.6 


23.7 


23.8 


23.9 


24.0 


25 


24.2 


24.3 


24.4 


24.5 


24.6 


24.6 


24.7 


24.8 


24.9 


25.0 


26 


25.2 


25.2 


25.3 


25.4 


25.5 


25.6 


25.7 


25.8 


25.9 


26.0 


27 


26.2 


26.2 


26.3 


26.4 


26.5 


26.6 


26.7 


26.8 


26.9 


27.0 


28 


27.] 


27.2 


27.3 


27.4 


27.5 


27.6 


27.7 


27.8 


27.9 


28.0 


29 


28.1 


28.2 


28.3 


28.4 


28.5 


28.6 


28.7 


28.8 


28.9 


29.0 


30 


29.1 


29.1 


29.2 


29.3 


29.4 


29.6 


29.7 


29.8 


29.9 


30.0 


31 


30.0 


30.1 


30.2 


30.3 


30.4 


30.5 


30.6 


30.8 


30.9 


31.0 


32 


31.0 


31.1 


31.2 


31.3 


31.4 


31.5 


31.6 


31.7 


31.9 


32.0 


33 


31.9 


32.0 


32.1 


32.3 


32.4 


32.5 


32.6 


32.7 


92.9 


33.0 


34 


32.9 


33.0 


33.1 


33.2 


33.3 


33.5 


33.6 


33.7 


33.9 


34.0 


35 


33.8 


33.9 


34.0 


34.2 


34.3 


34.5 


34.6 


34.7 


34.9 


35.0 




61 


62 


63 


64 


65 


m 


67 


68 


69 


70 


20 


20.1 


20.2 


20.2 


20.3 


20.4 


20.5 


20.6 


20.7 


20.9 


21.0 


21 


21.1 


21.2 


21.3 


21.4 


21.5 


21.6 


21.7 


21.8 


22.0 


22.1 


22 


22.1 


22.2 


22.3 


22.4 


22.5 


22.6 


22.7 


22.8 


23.0 


23.1 


23 


23.1 


23.2 


23.3 


23.4 


23.5 


23.6 


23.7 


23.8 


24.0 


24.1 


24 


24.1 


24.2 


24.3 


24.4 


24.5 


24.6 


24.7 


24.9 


• 25.0 


25.1 


25 


25.1 


25.2 


25.3 


25.4 


25.5 


25.6 


25.7 


25.9 


26.0 


26.1 


26 


26.1 


26.2 


26.3 


26.5 


26.6 


26.7 


26.8 


27.0 


27.1 


27.2 


27 


27.1 


27.3 


27.4 


27.5 


27.6 


27.7 


27.8 


28.0 


28.1 


28.2 


28 


28.1 


28.3 


28.4 


28.5 


28.6 


28.7 


28.8 


29.0 


29.1 


29.2 


29 


29.1 


29.3 


29.4 


29.5 


29.6 


29.7 


29.9 


30.1 


30.2 


30.3 


30 


30.1 


30.3 


30.4 


30.5 


30.7 


30.8 


30.9 


31.1 


31.2 


31.3 


31 


31.2 


31.3 


31.4 


31.5 


31.7 


31.8 


31.9 


32.1 


32.2 


32.4 


32 


32.2 


32.3 


32.5 


32.6 


32.7 


32.9 


33.0 


33.2 


33.3 


33.4 


33 


33.2 


33.3 


33.5 


33.6 


33.8 


33.9 


34.0 


34.2 


34.3 


34.5 


34 


34.2 


34.3 


34.5 


34.6 


34.8 


34.9 


35.0 


35.2 


35.3 


35.5 


35 


35.2 


35.3 


35 5 


35.6 


35.8 


35.9 


36.1 


36.2 


36.4 


36.5 



Directions.— Bring the temperature of the milk to within 10° from 60° F. 
Take the reading of the lactometer and that of the temperature of the milk; find 
the former in the first vertical column of the table and the latter in the first hori- 
zontal row of figures; the figure where the horizontal and vertical columns meet is 
the corrected lactometer reading; e. g., observed, 31.0 at 67° F ; corrected reading, 
31.9. 



Appendix. 



209 



Table V. Percent of solids not fat, corresponding to 
o to 6 percent, of fat, and lactometer readings of 
26 to 3<^- (See p. 85). 






Lactometer readings at 60° F. 


=3 


0^ 


26 


27 


28 


29 


30 


31 


32 


33 


34 


35 


36 







6.50 


6.75 


7.00 


7.25 


7.50 


7.75 


8.00 


8.25 


8.50 


8.75 


9.00 





0.1 


6.52 


6.77 


7.02 


7.27 


7.527.77 


8 02 


8.27 


8.52 


8.77 


9.02 


0.1 


0.2 


6.54 


6.79 


7.04 


7.29 


7.547.79 


8.04 


8.29 


8.54 


8.79 


9.04 


0.2 


0.3 


6.56 


6.81 


7.06 


7.31 


7.56 


7.81 


8.06 


8.31 


8.56 


8.81 


9.06 


0.3 


0.4 


6.58 


6.83 


7.08 


7.33 


7.58 


7.83 


8.08 


8.33 


8.58 


8.83 


0.08 


0.4 


0.5 


6.60 


6.85 


7.10 


7.35 


7.60 


7.85 


8.10 


8.35 


8.60 


8.85 


9.10 


0.5 


0.6 


6.62 


6.87 


7.12 


7.37 


7.62 


7.87 


8.12 


8.37 


8.62 


8.87 


9.12 


0.6 


0.7 


6.64 


6.89 


7.14 


7.39 


7.64 


7.89 


8.14 


8.39 


8.64 


8.89 


9.14 


0.7 


0.8 


6.66 


6.91 


7.16 


7.41 


7.66 


7.91 


8.16 


8.41 


8.66 


8.91 


9.16 


0.8 


0.9 


6.68 


6.93 


7.18 


7.43 


7.68 


7.93 


8.18 


8.43 


8.68 


8.93 


9.18 


0.9 


1.0 


6.70 


6.95 


7.20 


7.45 


7.70 


7.95 


8.20 


8.45 


8.70 


8.95 


9.20 


1.0 


1.1 


6.72 


i.97 


7 22 


7.47 


7.72 


7.97 


8.22 


8.47 


8.72 


8.97 


9.22 


1.1 


1.2 


6.74 


6.99 


7^24 


7.49 


7.74 


7.99 


8.24 


8.49 


8.74 


8.99 


9.24 


1.2 


1.3 


6.76 


7.01 


7.26 


7.51 


7.76 


8.01 


8.26 


8.51 


8.76 


9.01 


9.26 


1.3 


1.4 


6.78 


7.0^ 


7.28 


7.53 


7.78 


8.03 


8.28 


8.53 


8.78 


9.03 


9.28 


1.4 


1.5 


6.80 


7.05 


7.30 


7.55 


7.8u 


8.05 


8.30 


8.55 


8.80 


9.05 


9.30 


1.5 


1.6 


6.82 


7.07 


7.32 


7.57 


7.82 


8 07 


8.32 


8.57 


8.82 


9.07 


9.32 


1.6 


1.7 


6.84 


7.09 


7.34 


7.59 


7.84 


8.09 


8.34 


8.59 


8.84 


9.09!9.34 


J. 7 


1.8 


6.86 


7.11 


7.36 


7.61 


7.86 


8.11 


8.36 


8.61 


8.86 


9.11 


9.37 


1.8 


1.9 


6.88 


7.13 


7.38 


7.63 


7.88 


8.13 


8.38 


8.63 


8.88 


9.13 


9.39 


1.9 


2.0 


6.90 


7.15 


7.40 


7.65 


7.90 


8.15 


8.40 


8.66 


8.91 


9.16 


9.41 


2.0 


2.1 


6.92 


7.17 


7.42 


7.67 


7.92 


8.17 


8.42 


8.68 


8.93 


9.18 


9.43 


2.1 


2.2 


6.94 


7.19 


7.44 


7 69 


7.94 


8.19 


8.44 


8.70 


8.95 


9.20 


9.45 


2.2 


2.3 


6.96 


7.21 


7.46 


7.71 


7.96 


S.21 


8.46 


8.72 


8.97 


9.22 


9.47 


2."3 


2.4 


6.98 


7.23 


7.48 


7.73 


7.98 


8.23 


8.48 


8.74 


8.99 


9.24 


9.49 


2.4 


2.5 


7.00 


7.25 


7.50 


7.75 


8.00 


8.25 


8.50 


8.76 


9.01 


9.26 


9.51 


2.5 


2.6 


7.02 


7.27 


7.52 


7.77 


8.02 


8.27 


8.52 


8.78 


9.03 


9.28 


9.53 


2.6 


2.7 


7.04 


7.29 


7.54 


7.79 


8.04 


8.29 


8.54 


8.80 


9.05 


9.30 


9.55 


2.7 


2.8 


7.06 


7.31 


7.56 


7.81 


8.06 


8.31 


8.57 


8.82 


9.07 


9.32 


9.57 


2.8 


2.9 


7.08 


7.33 


7.58 


7.83 


8.08 


8.33 


8.598.84 


9.09 


9.34 


9.59 


2.9 



2IO Testing Milk and Its Products, 

Table Y. Percent, of solids not fat {Continued} 



o 


Lactometer readings at 60° F. 


'S 




26 


27 


28 


29 


30 


31 


32 


33 


34 


35 


36 




3.0 


7.10 


7.35 


7.60 


7.85 


8.10 


8.36 


8.61 


8.86 


9.11 


9.36 


9.61 


3.0 


3.1 


7.12 


7.37 


7.62 


7.87 


8.13 


8.38 


8.63 


8.88 


9.13 


9.38 


9.64 


3.1 


3.2 


7.14 


7.39 


7.64 


7.89 


8.15 


8.40 


8.65 


8.90 


9.15 


9.41 


9.66 


3.2 


3.3 


7.16 


7.41 


7.66 


7.92 


8.17 


8.42 


8.67 


8.92 


9.18 


9.43 


9.68 


3.3 


3.4 


7.18 


7.43 


7.69 


7.94 


8.19 


8.44 


8.69 


8.94 


9.20 


9.45 


9.70 


3.4 


3.5 


7.20 


7.45 


7.71 


7.96 


8.21 


8.46 


8.71 


8.96 


9.22 


9.47 


9.72 


3.5 


3.6 


7.22 


7.48 


7.73 


7.98 


8.23 


8.48 


8.73 


8.98 


9.24 


9.49 


9.74 


3.6 


3.7 


7.24 


7.50 


7.75 


8.00 


8.26 


8.50 


8.75 


9.00 


9.26 


9.51 


9.76 


3.7 


3.8 


7.26 


7.52 


6.77 


8.02 


8.27 


8.52 


8.77 


9.02 


9.28 


9.53 


9.78 


3.8 


3.9 


7.28 


7.54 


7 79 


8.04 


8.29 


8.54 


8.79 


9.04 


9.30 


9.55 


9.80 


3.9 


4.0 


7.30 


7.56 


7.81 


8.06 


8.31 


8.56 


8.81 


9.06 


9.32 


9.57 


9.83 


4.0 


4.1 


7.32 


7.58 


7.83 


8.08 


8.33 


8.58 


8.83 


9.08 


9.34 


9.59 


9 85 


4.1 


4.2 


7.34 


7.60 


7.85 


8.10 


8.35 


8.60 


8.85 


9.11 


9.36 


9.62 


9.87 


4.2 


4.3 


7.36 


7.62 


7.87 


8.12 


8.37 


8.62 


8.88 


9.13 


9.38 


9.64 


9.89 


4.3 


4.4 


7.38 


7.64 


7.89 


8.14 


8.39 


8.64 


8.90 


9.15 


9.40 


9.66 


9.91 


4.4 


4.5 


7.40 


7.66 


7.91 


8.16 


8.41 


8.66 


8.92 


9.17 


9.42 


9.68 


9.93 


4.5 


4.6 


7.43 


7.68 


7.93 


8.18 


8.43 


8.68 


8.94 


9.19 


9.44 


9.70 


9.95 


4.6 


4.7 


7.45 


7.7U 


7.95 


8.20 


8.45 


8.70 


8.96 


9.21 


9.46 


9.72 


9.97 


4.7 


4.8 


7 47 


7.72 


7.97 


8.22 


8.47 


8.72 


8.98 


9.23 


9.48 


9.74 


9.99 


4.8 


4.9 


7.49 


7.74 


7.99 


8.24 


8.49 


8.74 


9.00 


9.25 


9.50 


9.76 


10.01 


4.9 


5.0 


7.51 


7.76 


8.01 


8.26 


8.51 


8.76 


9.02 


9.27 


9.52 


9.78 


10.03 


5.0 


5.1 


7.53 


7.78 


8.(3 


8.28 


8.53 


8.79 


9.04 


9.29 


9.54 


9.80 


10.05 


5.1 


5.2 


7.55 


7.80 


8.05 


8.30 


8.55 


8.81 


9.06 


9.31 


9.56 


9.82 


10.07 


5.2 


5.3 


7.f>7 


7.82 


8.07 


8.32 


8.57 


8.88 


9.08 


9.33 


9.58 


9.84 


10.09 


5.3 


5.4 


7.59 


7.84 


8.09 


8.34 


8.60 


8.85 


9.10 


9.36 


9.61 


9.86 


10.11 


5.4 


5.5 


7.61 


7.86 


8.11 


8.36 


8.62 


8.87 


9.12 


9.389.68 


9.88 


10.13 


5.5 


5.6 


7.68 


7.88 


3.13 


8.39 


8.64 


8.89 


9.15 


9.40 9.65 


9.90 


10.15 


5.6 


5.7 


7.65 


7.90 


8.15 


8.41 


8.66 


8.91 


9.17 


9.42,9.67 


9.92 


10.17 


5.7 


5.8 


7.67 


7.92 


8.17 


8.43 


8.68 


8.94 


9.19 


9.44 9.69 


9.94 


10.19 


5.8 


5.9 


7.69 


7.94 


8.20 


8.45 


8.70 


8.96 


9.21 


9.469.71 


9.96 


10.22 


5.9 


6.0 


7.71 


7.96 


8.22 


8.47 


8.72 


8.98 


9.23 


9.48 9.73 

1 


9.98 


10.24 


6.0 



Aj>fendix. 211 

Directions for Use of Tables VI, VH, and IX. 

TABLE VI. Find the test of the milk in the first or last hori- 
zontal row of figures; the amounts of fat in ten thousand, thou- 
sands, hundreds, tens, and units of pounds of milk are then given 
in this vertical column. By adding the corresponding figures in 
any given quantity of milk, the total quantity of butter fat con- 
tained therein is obtained. 

Example. How many pounds of fat is contained in 8925 lbs. of milk testing 3.65 
percent? On p. 21.3, second column the test 3.66 is found, and by going downward 
in this column we have: 

8000 lbs 292, lbs. 

900 " 32.9 " 

20 " 7 " 

5 " 2 " 

8925 lbs. of milk. 325 8 lbs. of fat. 

8925 lbs. of milk testing 3.65 percent, therefore, contains 325.8 lbs. of butter fat. 

TABLE VII. The price per pound is given in the outside ver- 
tical columns.'and the freight of butter fat in the upper and lower 
horizontal row of figures. The corresponding tens of pounds are 
found by moving the decimal point one place to the left; the units, 
by moving it two, and the tenths of a pound, by moving it three 
places to the left. The use of the table is, otherwise, as explained 
above. 

Example.^ How much money is due for 325.8 lbs. of butter fat, at Xhy^ cents per 
pound? In the horizontal row of figures beginning with 15^, we find: 

.300 lbs $46.50 

20 " 3.10 

5 " 77 

.8 " 12 

325. 8 lbs. $50. 49 

325.8 lbs. of butter fat at 15 3^ cents per pound, therefore, is worth ^50.49. 

TABLE IX, Find the test of milk in the upper or lower hori- 
zontal row of figures. The amount of butter likely to be made 
from ten thousand, thousands, hundreds, tens, and units of pounds 
of milk are then given in this vertical column. The use of the 
table is, otherwise, as explained above in case of table VI. 

Example. How much butter will 5845 lbs. of milk testing 3.8 percent be apt to 
make under good creamery conditions? In the column headed 3.8, we find: 

5000 lbs 2C9.0 lbs. 

800 " 33.4 " 

40 " 1.7 " 

5 " 2 " 

5845 lbs. 244. 3 lbs. 

5845 lbs. of milk testing 3.8 percent of fat will make about 244.3 lbs. of butter, 
under conditions similar to those explained on pp. 168-69 of the present work. 



212 Testing- Milk and Its Products, 

Table VI. Lbs. of fat in i to 10,000 lbs. of milk, testing 
3.0 to 5.35 percent. (See p. 211). 



1 


3.00 


3.05 


3.10 


3.15 


3.20 


3.25 


3.30 


3.35 


3.40 


3.45 


3.50 


3.55 


t 


Milk 


























Milk 


lbs. 


























lbs. 


10, COO 


300 


305 


310 


315 


320 


325 


330 


335 


340 


345 


350 


355 


10, 000 


9,000 


270 


275 


279 


284 


289 


293 


297 


302 


306 


311 


315 


320 


9,000 


8,000 


240 


244 


248 


252 


256 


260 


264 


268 


272 


276 


280 


284 


8,000 


7,000 


210 


214 


217 


221 


224 


228 


231 


235 


238 


242 


245 


249 


7,000 


6,000 


180 


183 


186 


189 


192 


195 


198 


201 


204 


207 


210 


213 


6,000 


5,000 


150 


168 


155 


158 


160 


163 


165 


168 


170 


173 


175 


178 


5,000 


4,000 


120 


122 


124 


126 


128 


130 


132 


134 


136 


138 


140 


142 


4,000 


3,000 


90.0 


91.5 


93.0 


94.5 


96.0 


97.5 


99.0 


101 


102 


104 


105 


107 


3, 000 


2, 000 


60.0 


61.0 


62.0 


63.0 


64.0 


65.0 


66.0 


67.0 


68.0 


69.0 


70.0 


71.0 


2,000 


1,000 


30.0 


30.5 


31.0 


31.5 


32.0 


32.5 


33.0 


33.5 


34.0 


34.5 


35.0 


35.5 


1,000 


900 


27.0 


27.5 


27.9 


28.4 


28.8 


29.3 


29.7 


30.2 


30.6 


31.1 


31.5 


32.0 


900 


800 


24.0 


24.4 


24.8 


25.2 


25.7 


26.0 


26.4 


26.8 


27.2 


27.6 


28.0 


28.4 


800 


700 


21.0 


21.4 


21.7 


22.1 


22.4 


22.8 


23.1 


23.5 


23.8 


24.2 


24.5 


24.9 


700 


600 


18.0 


18.3 


18.6 


18.9 


19.2 


19.5 


19.8 


20.1 


20.4 


20.7 


21.0 


21.3 


600 


500 


15.0 


15.3 


15. 5 


15.8 


16.0 


16.3 


16.5 


16.8 


17.0 


17.3 


17.5 


17.8 


500 


400 


12.0 


12.2 


12.4 


12.6 


12.8 


13.0 


13.2 


13.4 


13.6 


13.8 


14.0 


14.2 


400 


300 


9.0 


9.2 


9.3 


9.5 


9.6 


9.8 


9.9 


10.1 


10.2 


10.4 


10.5 


10.7 


300 


200 


6.0 


6.1 


6.2 


6.3 


6.4 


6.5 


6.6 


6.7 


6.8 


io.9 


7.0 


7.1 


200 


100 


3.0 


3.1 


3.1 


3.2 


3.2 


3.3 


3.3 


3.4 


3.4 


3.5 


3.5 


3.6 


100 


90 


2.7 


2.8 


2.8 


2.8 


2.9 


2.9 


3.0 


3.0 


3.1 


3.1 


3.2 


3.2 


90 


80 


2.4 


2.4 


2.5 


2.5 


2.6 


2.6 


2.6 


2.7 


2.7 


2.8 


2.8 


2.8 


80 


70 


2.1 


2.1 


2.2 


2.2 


2.2 


2.3 


2.3 


2.3 


2 4 


2.4 


2.5 


2.5 


70 


60 


1.8 


1.8 


1.9 


1.9 


1.9 


2.0 


2.0 


2.0 


2.0 


2.1 


2.1 


2.1 


60 


50 


1.5 


1.5 


1.6 


1.6 


1.6 


1.6 


1.7 


1.7 


1.7 


1.7 


1.8 


1.8 


50 


40 


1.2 


1.2 


1.2 


1.3 


1.3 


1.3 


1.3 


1.3 


1.4 


1.4 


1.4 


1.4 


40 


30 


.9 


.9 


.9 


.9 


1.0 


1.0 


1.0 


1 


1.0 


1.0 


1.1 


1.1 


30 


20 


.6 


.6 


.6 


.6 


.6 


.7 


.7 


.7 


7 


.7 


.7 


.7 


20 


10 


.3 


.3 


.3 


.3 


.3 


.3 


.S 


.3 


.3 


.3 


.4 


.4 


10 


9 


.3 


.3 


.0 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


9 


8 


.2 


.2 


2 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


8 


7 


.2 


.2 


.2 


.2 


.2 


2 


2 


.2 


.2 


•2| 


.2 


.2 


/ 


6 


.2 


2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2I 


.2 


.2 


6 


5 


2 


.2 


.2 


.2 


.2 


9 


.2 


.2 


.2 


2 


.2 


2 


5 


4 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


4 


3 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


3 


2 

1 


.1 


.1 


...".! 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


2 
1 


■« 


3.00 


3.05 


3.10 


3.15 


3.20 


3.25 


3.30 


3.35 


3.40 


3.45 


3.50 


3.55 


^ 


H 
















1 











Appendix. 213 

Table TI. Lbs. of fat in 1 to 10,000 lbs. of milk {Continued) 





3.60 


3.65 


3.70 


3.75 


3.80 


3.85 


3.90 


3.95 


4.00 


4.05 


4.10 


4.15 


I 


Milk 


























Mlik 


lbs. 


























lbs. 


10, 000 


360 


365 


370 


375 


380 


385 


390 


395 


400 


405 


410 


415 


10, 000 


9,000 


324 


329 


333 


338 


342 


347 


351 


356 


360 


365 


369 


374 


9,000 


8,000 


288 


292 


296 


300 


304 


308 


312 


316 


320 


324 


328 


332 


8,000 


7,000 


252 


256 


269 


263 


266 


270 


273 


277 


280 


284 


287 


291 


7,000 


6,000 


216 


219 


222 


225 


228 


231 


234 


237 


240 


243 


246 


249 


6,000 


5, 000 


180 


183 


185 


188 


190 


193 


195 


198 


200 


203 


205 


208 


5,000 


4,000 


144 


146 


148 


150 


152 


154 


156 


158 


160 


162 


164 


166 


4,000 


3,000 


108 


110 


111 


113 


114 


116 


117 


119 


120 


122 


123 


125 


3,000 


2,000 


72.0 


73.0 


74.0 


75.0 


76.0 


77.0 


78.0 


79.0 


80.0 


81.0 


82.0 


83.0 


2,000 


1,000 


36.0 


36.5 


37.0 


37.5 


38.0 


38.5 


39.0 


39.5 


40.0 


40.5 


41.0 


41.5: 


1,000 


900 


32.4 


32.9 


33.3 


33.8 


34.2 


34.7 


35.1 


35.6 


36.0 


36.5 


36.9 


37.4 


900 


800 


28.8 


29.2 


29.6 


30.0 


30.4 


30.8 


31.2 


31.6 


32.0 


32.4 


32.8 


33.2 


800 


700 


25.2 


25.6 


25.9 


26.3 


26.6 


27.0 


27.3 


27.7 


28.0 


28.4 


28.7 


29.1 


700 


600 


21.6 


21.9 


22.2 


22.5 


22.8 


23.1 


23.4 


23.7 


24.0 


24.3 


24.6 


24.9 


600 


500 


18.0 


18.3 


18.5 


18.8 


19.0 


19.3 


19.5 


19.8 


20.0 


20.3 


20.5 


20.8 


500 


400 


14.4 


14.6 


14.8 


15.0 


15.2 


15.4 


15.6 


15.8 


16. C 


16.2 


16.4 


16 6 


400 


300 


10.8 


11.0 


11.3 


11.3 


11.4 


11.6 


11.7 


11.9 


12.0 


12.2 


12.3 


12.5 


300 


200 


7.2 


7.3 


7.4 


7.5 


7.6 


7.7 


7.8 


7.9 


8.0 


8.] 


8.2 


8.3 


200 


100 


3.6 


3.7 


3.7 


3.8 


3.8 


3.9 


3.9 


4.0 


4.0 


4.1 


4.1 


4.2 


100 


90 


3.2 


3.3 


3.3 


3.4 


3.4 


3.5 


3.5 


3.6 


3.6 


3.7 


3.7 


3.7i 


90 


80 


2.9 


2.9 


3.0 


3.0 


3.0 


3.1 


3.1 


3.2 


3.2 


3.2 


3.3 


3.3 


80 


70 


2.5 


2.6 


2.6 


2.6 


2.7 


2.7 


2.7 


2.8 


2.8 


2.8 


2.9 


2.9 


70 


60 


2.2 


2.2 


2.2 


2.3 


2.3 


2.3 


2.3 


2.4 


2.4 


2.4 


2.5 


2.5 


60 


50 


1.8 


1.8 


1.9 


1.9 


1.9 


1.9 


2.0 


2.0 


2.0 


2.0 


2.1 


2.1 


50 


40 


1.4 


1.5 


1.5 


1.5 


1.5 


1.5 


1.6 


1.6 


1.6 


1.6 


1.6 


1.7 


40 


30 


1.1 


1.1 


1.1 


1.1 


1.1 


1.2 


1.2 


1.2 


1.2 


1.2 


1.2 


1.2 


30 


20 


.7 


.7 


.7 


.8 


.8 


.& 


.8 


.8 


.8 


.8 


.8 


.8 


20 


10 


.4 


.4 


A 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


. .4 


.4 


10 


9 


.3 


.3 


.3 


.3 


.3 


.3 


.4 


.4 


.4 


.4 


4 


.4 


9 


8 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


8 


7 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


7 


6 


2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


6 


5 


2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


5 


4 


!l 


.1 


.1 


.2 


.2 


2 


.2 


.2 


.2 


.2 


.2 


.2 


4 


3 


.1 


.1 


.1 


.1 


.1 


'.1 


.1 


.1 


.1 


.1 


.1 


.1 


3 


2 
1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 



.1 


2 
1 




3.60 


3.65 


3.70 


3.76 


3.80 


3.85 


3.90 


3.95 


4.00 


4.05 


4.10 


4.15 




i 
^ 


I 



214 



Testing Milk and Its Products. 



Table YI. Lbs. of fat in 1 to 10,000 lbs. of milk {Continued) 





4.20 


4.25 


4.30 


1 
4.35 


1 
4.40 

1 


4.45| 


4.50 


4.56 


4.60 


4.65 


4.70 


1 
4.75 


t 


Milk 


























Milk 


lbs. 


























lbs. 


10,0001= 420 


425 


430 


435 


440 


445 


450 


455| 


460 


465 


470 


475 


10, 000 


9,000! 378 


383 


387 


392 


396 


40l| 405 


410 


4141 


419 423| 


428 


9,000 


8,000 


336 


340 


344 


348 


352 


356 360 


364 


368 


372 


376 


380 


8,000 


7,000 


294 


298 


301 1 


305 


308 


312[: 315 


319 


322 


326 


329 


333 


7,000 


6,000 


252 


255 


258' 


261 


264 


267;' 270 


273 


276 


279 


282 


285 


6,000 


5, 000 


210 


213 


215 


218 


220 


223|' 225 


228 


230 


2331 


235 


238 


5,000 


4,000 


168 


170 


172 


174 


176 


178li 180l 


182 


184 


186! 188 


190 


4,000 


3,000 


126 


128 


129 


131 


132 


13411 135 


137 


138 


140| 141 


14311 3,000 


2,000 


84.0 


85.0 


86.0 


87.0 


88.0 


89.0ll90.0 


91.0 


92.0 


93.094.0 


95.0 


2,000 


1,000 


42.0 


42.5 


43.0 


43.5 


44.0 


44.5115.0 


45.5 


46.0 


46.5 47.0 


47.5 


1,000 


900':'37.8 


38.3 


38.7 


39.2 


39.6 


40.1140.5 


41.0 


41.4 


41.9142.3 


42.8 


900 


800 33.6 


34.0 


34.4 


34.835.2 


35.6:136.0 


36.4 


36.8 


37.2 37.6 


38.0 


800 


700 29.4 


29.8 


30.1 


30.5 


30.8 


31.2131.5 


31.9 


32.2 


32.6 


32.9 


33.3 


700 


600 25.2 


25.5 


25.8 


26.1 


26.4 


26.7j27.0 


27.3 


27.6 


27.9 


28.2 


28.5 


600 


500 21.0 


21.3 


21.5 


21.8 


22.0 


22.3I22.5 


22.8 


23.0 


23.3 


23.5 


23.8 


500 


400 16.8 


17,0 


17.2 


17.4 


17.6 


17.8 18.0 


18.2 


18.4 


18.6 


18.8 


19.0 


400 


300:12.6 


12.8 


12.9 


13.1 


13.2 


13.4 13.5 


13.7 


13.8 


14.0 


14.1 


14.3 


300 


200 8.4 


8.5 


8.6 


8.7 


8.8 


8.9 9.0 


9.1 


9.2 


9.3 


9.4 


9.51 200 


100 


4.2 


4.3 4.3 


4.4 


4.4 


4.5;: 4.5 


4.6 


4.6 


4.7 


4.7 


4.8:, 100 


90 


3 8 


3 8 


3.9 


3.9 


4.0 


4.01 


4.1 


4.1 


4.1 


4.2 


4.2 


4.3:1 90 


80 


3 4 


3,4 


3.4 


3.5 3.5 


3.6! 


3.6 


3.6 


3.7 


3.7 


3.8 


3.8 


80 


70 


1 2 9 


3.0 


3.0 


3.0 


3.1 


3.1' 


3.2 


3.2 


3.2 


3.3 


3.3 


3.3 


70 


60 


2,5 


2.6 


2.6 


2.6 


2.6 


2.7 


2.7 


2.7 


2.8 


2.8 


2.8 


2.9 


60 


50 


2.1 


2.1 


2.2 


2.2 


2.2 


2.2 


2.3 


2.3 


2.3 


2.3 


2.4 


2.4 


50 


40 


1 7 


1.7 


1.7 


1.7 


1.8 


1.8 


1.8 


1.8 


1.8 


1.9 


1.9 


1.9 


40 


80 


1.3 


1.3 


1.3 


1.3 


1.3 


1.3 


1.4 


1.4 


1.4 


1.4 


1.4 


1.4 


' 30 


20 


8 


9 


.9 


.9 


.9 


.9 


.9 


.9 


.9 


.9 


9 


1.0 


i 20 


10 


.4 


.4 


.4 


.4 


.4 


.4 


.5 


.5 


.5 


.5 


.5 


.5 


10 


9 


4 


4 


,4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


i 

9 


8 


3 


,3 


,3 


.3 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 


8 


7 


3 


,3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


7 


6 


,3 


,3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


6 


5 


? 


2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


5 


4 


V 


2 


,2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


.2 


4 


3 


1 


1 


1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


3 


2 
1 


.1 


.1 


.1 


.1 


.1 


.1 


i. ...'.. 


.1 


.1 


.1 


.1 


.1 


2 

1 


1 


4.2C 


4.25 


4.30 


4.35 


4.4C 


4.45 


4.50 


4.55 


4.6C 


4.65 


4.70 


4.75 


t 



Appendix, 



21 



Table TI. Lbs. of fat in 1 to 10,000 lbs. of milk ( C 


on tinned) 


1 


4.80 


4.85 


4.90 


4.95 


5.00 


5.05 


5.10 


5.15 


5.20 


5.25 


5.30 


5.35 




Milk 


























1 Milk 


lbs. 


























1 lbs. 


10, 000 
9,000 


480 


485 


490 


495 


500 


505 


510 


515 


520 52o 


530 535 


10,000 


432 


437 


441 


446 


450 


455 


459 


464 


468! 4731 477! 482 


i 9, 000 


8,000 


384 


388; 392 


396 


400 


404 


408 


412 


416 420 422! ^28 


8,000 


7, 000 


i 336 


340; 343 


347 


350 


354 


357 


361 


364 368 371 375 


: 7, 000 


6,000 


288 


291! 294 


297 


300 


303 


306 


309 


312 315 318 321 


6,000 


5,000 


240 


243i 245 


248 


250 


243 


255 


258 


260 263 265 268 


1 5,000 


4,000 


192 


194' 196 


198 


200 


202 


204 


206 


208 210 212 214 


4,000 


3,000 


144 


146 147 


149 


150 


152 


153 


155 


156 158 159 161 


3,000 


2, 000 


96.0 


97.098.0 


99.0 


100 


101 


102 


103 


104 105 106 107 


2,000 


1,000 


48.0 


48.5 49.0 


49.5 


50.0 


50.5 


51.0 


51.5 


52.0 52.5 53.0 53.5 


1,000 


900 


43.2 


43.7 44.1 


44.6 


45.0 


45.5 


45.7 


46.4 


46.8 47.3 47.7 48.2 


900 


800 


38.4 


38.839.2 


39.6 


40.0 


40.4 


40.8 


41.2 


41.642.042.442.8 


800 


700 


33.6 


34.034.3 


34.7 


35.0 


35.4 


35.7 


36.1 


36 4 36.8 37.1137.5 


700 


600 


28.8 


29.129.4 


29.7 


30.0 


30.3 


30.6 


30.9 


31.231.531.8^32.1 


600 


500 


24.0 


24.324.5 


24.8 


25 


25.3 


25.5 


25.8 


26.0 26.3 26.626.8 


500 


400 


19.2 


19.419.6 


19.8 


20.0 


20.2 


20.4 


20.6 


20.821.021.221.4 


400 


300 


14.4 


14.614.7 


14.9 


15.0 


15.2 


15.3 


15.5 


15.6 15.8 15.9 16.1 


300 


200 


9 6' 9.71 9.8 


9.9 


10.0 


10.1 


10.2 


10.3 


10.410.510.610.7 


200 


100 


4.8 4.9 


4.9 


5.0 


5.0 


5.1 


5.1 


5.2 


5.2 


5.3 5.3 


5.4 


100 


90 


4.3 4.4 


4.4 


4.5 


4.5 


4.5 


4.6 


4.6 


4.7 


4.7 4.8 


4.8 


90 


80 


3.8 3.9 


3.9 


4.0 


4.0 


4.0 


4.1 


4.1 


4.2| 4.2 4.2' 4.3 


80 


70 


3.4 3.4 


3.4 


3.5 


3.5 


3.5 


3.6 


3.6 


3.6 3.7 3.71 3.7 


1 '0 


60 


2.9 2.9 


2.9 


3.0 


3.0 


3.0 


3.1 3.1 


3.1 3.2' 3.2 3.2 


i 60 


50 


2.4 2.4 


2.5 


2.5 


2.5 


2.5 


2.6 2.6 


2.6 2.6| 2.7 2.7 


50 


40 


1.9 1.9 


2.0 


2.0 


2.0 


2.0 


2.01 2.1 


2.1| 2.1 2.l| 2.1 


40 


30 


1.4 1.5 


1.5 


1.5 


1.5 


1.5 


1.5 1.5 


1.6j 1.6 l.el 1.6 


30 


20 


1.0 1.0 


1.0 


1.0 


1.0 


1.0 


1.0 


1.0 


1.0 1.1 1.1} 1 1 


20 


10 


.5 .5 


.5 


.5 


.5 


.5 


.5 


.5 


.5 .5j .5 .5 


10 


9 


.4 .4 


.4 


.4 


.5 


.5 


.5 


.5 


.5 .5i .5' .5 


9 


8 


.4 .4 


.4 


.4 


.4 


.4 


.4 


.4 


.4 .4 .4 .4 


8 


7 


.3 .3 


.3 


.3 


.4 


.4 


.4 


.4 


.4 .4 .4 .4 


7 


6 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 .3 .3 .3 


6 


5 


.2 


.2 


.2 


.2 


.3 


.3 


.3 


.3 


.3 .3 .3 .3 


5 


4 


.2 


.2 


.2 


2 


.2 


.2 


.2 


2 


.2 .2 .2 .2 


4 


3 


.1 


.1 


.1 


A 


.2 


.2 


.2 


2 


.21 .2! .2 .2 


3 


2 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.li .1 .1 


.1 


2 


1 










.1 


.1 


.1 


.1 


.1 


.1 .1 


.1 


1 




















4.80 


4.85 


4.90 


4.95 


5.00 


5.05 


5.10 


5.15 


5.20 


5.25 


5.30 


5.35 


S 



2l6 



Testing Milk and Its Products, 



Table VII. Amount due for butter fat, in dollars and cents, at 12 
to 25 cents per pound. 



11 


Pounds of butter fat. 


11 


"1 


1,000 


900 


800 


700 


600 


500 


400 


300 


200 


100 


If 




% 


$ 


% 


$ 


$ 


$ 


% 


$ 


$ 


$ 




12 


120.00 


108.00 


96.00 


84.00 


72.00 


60.00 


48.00 


36.00 


24.00 


12.00 


12 


12i 


122.50 


110.25 


98.00 


85.75 


73.50 


61.25 


49.00 


36.75 


24.50 


12.25 


Vl\ 


12^ 


125.00 


112.50 


100.00 


87.50 


75.00 


62.50 


50.00 


37.50 


25.00 


12.60 


12^ 


121 


127.50 


114.75 


102.00 


89.25 


76.50 


63.75 


51.00 


38.25 


25.50 


12.75 


121 


13 


130.00 


117.00 


104.00 


91.00 


78.00 


65.00 


52.00 


39.00 


26.00 


13.00 


13 


13i 


132.50 


119.25 


106.00 


92.75 


79.50 


66.25 


53.00 


39.75 


26.50 


13.25 


\Z\ 


13^ 


135.00 


121.50 


108.00 


94.50 


81.00 


67.50 


54.00 


40.50 


27.00 


13.50 


13* 


13f 


137.50 


123.75 


110.00 


96.25 


82.50 


68.75 


55.00 


41.25 


27.50 


13.75 


131 


14 


140.00 


126.00 


112.00 


98.00 


84.00 


70.00 


56.00 


42.00 


28.00 


14.00 


14 


14i 


142.50 


128.25 


114.00 


99.75 


85.50 


71.25 


67.00 


42.75 


28.50 


14.25 


14J 


14i 


145.00 


130.50 


116.00 


101.50 


87.00 


72.50 


58.00 


43.50 


29.00 


14 50 


14^ 


14| 


147.50 


132.75 


118.00 


103.25 


88.50 


73.75 


59.00 


44.25 


29.50 


14.75 


141 


15 


150.00 


135.00 


120.00 


105.00 


90.00 


75.00 


60.00 


45.00 


30.00 


15.00 


15 


15i 


152.50 


137.25 


122.00 


106.75 


91.50 


76.25 


61.00 


45.76 


30.50 


15.25 


15i 


15^ 


155.00 


139.50 


124.00 


108.50 


93.00 


77.50 


62.00 


46.50 


31.00 


15.50 


15^ 


15f 


157.50 


141.76 


126.00 


110.25 


94.50 


78.75 


63.00 


47.25 


31.50 


15 75 


151 


16 


160.00 


144.00 


128.00 


112.00 


96.00 


80.00 


64.00 


48.00 


32.00 


16.00 


16 


16i 


162.50 


146.25 


130.00 


113. 7^ 


97.50 


81.25 


65.00 


48.75 


32.50 


16.25 


16J 


16^ 


165.00 


148. 5C 


132.00 


115.50 


99.00 


82.50 


66.00 


49.50 


33.00 


16.50 


16^ 


161 


167.50 


150.75 


134.00 


117.25 


100.50 


83.75 


67.00 


60.25 


33.50 


16.75 


16| 


17 


170.00 


153.00 


136.00 


119.00 


102.00 


85.00 


68.00 


51.00 


34.00 


17.00 


17 


n\ 


172.50 


155.25 


138.00 


120.75 


103.50 


86.25 


69.00 


51.75 


34.50 


17.25 


17i 


17^ 


175.00 


157.50 


140.00 


122.50 


105.00 


87.50 


70.00 


52.50 


35.00 


17.50 


17i 


17| 


177.50 


159.75 


142.00 


124.25 


106.50 


87.75 


71.00 


53.25 


35.50 


17.75 


171 


18 


180.00 


162.00 


144.00 


126.00 


108 CO 


90.00 


72.00 


54.00 


36.00 


18.00 


18 


I84 


182.50 


164.25 


146.00 


127.75 


109.50 


91.25 


73.00 


54.75 


36.50 


18.25 


181- 


18i 


185.00 


166.50 


148.00 


129.50 


111.00 


92.50 


74.00 


55.50 


37.00 


18.50 


18^ 


18- 


187.50 


168.75 


150.00 


131.25 


112.50 


93.75 


75.00 


56.25 


37.50 


18.75 


18| 




1,000 


900 


800 


700 


600 


500 


400 


300 


200 


100 





Appendix. 217 

Table YII. Amount due for butter fat {Continued.) 



(1 s 


Pounds of butter fat. 








<-' Q 


s.§ 












S.S 


8-« 






















8-2 


H 


1,000 


900 


800 


700 


600 


500 


400 


300 


200 


100 


•r a 
^1 




$ 


1 


$ 


$ 


$ 


$ 


$ 


$ 


$ 


$ 




19 


190.00 


171.00 


152.00 


133.00 


114.00 


95.00 


76.00 


57.00 


38.00 


19.00 


19 


19,1 


192.50 


173.25 


154.00 


134.75 


115.50 


96.25 


77.00 


57.75 


38.50 


19.25 


191- 


19^ 


195.00 


175.50 


156.00 


136.50 


117.00 


97.50 


78.00 


58.50 


39.00 


19.50 


191 


191 


197.50 


177.75 


158.00 


138.25 


118.50 


98.75 


79.00 


59.25 


39.50 


19.75 


19f 


20 


200.00 


180.00 


160.00 


140.00 


120.00 


100.00 


80.00 


60.00 


40.00 


20.00 


20 


20| 


202.50 


182.25 


162.00 


141.75 


121.50 


101.25 


81.00 


60.75 


40.50 


20.25 


20i 


20i 


205.00 


184.50 


164.00 


143.50 


123.00 


102.50 


82.00 


61.50 


41.00 


20.50 


20* 


20f 


207.50 


186.75 


166.00 


145.25 


124.50 


103.75 


83.00 


62.25 


41.50 


20.75 


20f 


21 


210.00 


189.00 


168.00 


147.00 


126.00 


105.00 


84.00 


63.00 


42.00 


21.00 


21 


2U 


212.50 


191.25 


170.00 


148.75 


127.50 


106.25 


85.00 


63.75 


42.50 


21.25 


2U 


21i 


215.00 


193.50 


172.00 


150.50 


129.00 


107.50 


86.00 


64.50 


43.00 


21.50 


2U 


21| 


217.50 


195.75 


174.00 


152.25 


130.50 


108.75 


87.00 


65.25 


43.50 


21.75 


21| 


22 


220.00 


198.00 


176.00 


154.00 


132.00 


110.00 


88.00 


66.00 


44.00 


22.00 


22 


22| 


222.50 


200.25 


178.00 


155.75 


133.50 


111.25 


89.00 


66.75 


44.50 


22.25 


22i 


22^ 


225.00 


202.50 


180.00 


157.50 


135.00 


112.50 


90.00 


67.50 


45.00 


22.50 


22J 


221 


227.50 


204.75 


182.00 


159.25 


136.50 


113.75 


91.00 


68.25 


45.50 


22.75 


22| 


23 


230.00 


207.00 


184.00 


161.00 


138.00 


115.00 


92.00 


69.00 


46.00 


23.00 


23 


234I 


232.50 


209.25 


186.00 


162.75 


139.50 


116.25 


93.00 


69.75 


46.50 


23.25 


2Sk 


23i 


235.00 


211.50 


188.00 


164.50 


141.00 


117.50 


94.00 


70.50 


47.00 


23.50 


23h 


23| 


237.50 


213.75 


190.00 


166.25 


142.50 


118.75 


95.00 


71.25 


47.50 


23.75 


23| 


24 


240.00 


216.00 


192.00 


168.00 


144.00 


120.00 


96.00 


72.00 


48.00 


24.00 


24 


241 


242.50 


218.25 


194.00 


169.75 


145.50 


121.25 


97.00 


72.75 


48.50 


24.50 


24i 


24^ 


245.00 


220.50 


196.00 


171.50 


147.00 


122.50 


98 00 


73.50 


49.00 


24. 5( 


24* 


241 


247.50 


222.75 


198.00 


173.25 


148.50 


123.75 


99.00 


74.25 


49.50 


24.75 


24f 


25 


250.00 


225.00 


200.00 


175.00 


150.0U 


125.00 


100.00 


75. 0( 


50.00 


25. 0( 


25 




1,000 


900 


800 


700 


600 


500 


400 


300 


200 


100 





(For directions for use, see page 211) 



2l8 



Testing Milk and Its Products. 



Table VIII. Relative value tables. 

(For directions for use, see pp. 180-81). 







Pric 


E OF MILK PER 100 POUNDS, 


IN DOLLARS AND CENTS. 




3.0 


.30 


.31 


.33 


.3i 


.36 


.37 


.39 


.40 


.42 


.43 


.45 


3.1 


.31 


.33 


.34 


.36 


.37 


.39 


.40 


.42 


.43 


.45 


.46 


3.2 


.32 


.34 


.35 


.37 


.38 


.40 


.42 


.43 


.45 


.46 


.48 


3.3 


.33 


.85 


.36 


.38 


.40 


.41 


.43 


.45 


.46 


.48 


.49 


3.4 


.34 


.36 


.37 


.39 


.41 


.42 


.44 


.46 


.48 


.49 


.51 


3.5 


.35 


.37 


.38 


.40 


.42 


.44 


.45 


.47 


.49 


.51 


.52 


3.6 


.36 


.38 


.40 


.41 


.43 


.45 


.47 


.49 


.50 


.52 


.54 


3.7 


.37 


.39 


.41 


.43 


.44 


.46 


.48 


.50 


.52 


.54 


.55 


3.8 


.38 


.40 


.42 


.44 


.46 


.47 


.49 


.51 


.53 


.55 


.57 


3.9 


.39 


.41 


.43 


.45 


.47 


.49 


.51 


.53 


.55 


.57 


.58 


4.0 


.40 


.42 


.44 


.46 


.48 


.50 


.52 


.54 


.56 


.58 


.60 


4.1 


.41 


.43 


.45 


.47 


.49 


.51 


.53 


.55 


.57 


.59 


.61 


4.2 


.42 


.44 


.46 


.48 


.50 


.52 


.55 


.57 


.59 


.61 


.63 


4.3 


.43 


.45 


.47 


.49 


.52 


.54 


.56 


.58 


.60 


.62 


.64 


4.4 


.44 


.46 


.48 


.51 


.53 


.55 


.57 


.59 


.62 


.64 


M 


4.5 


.45 


.47 


.49 


.52 


.54 


.56 


..■^8 


.61 


.63 


.6) 


.67 


4.6 


.46 


.48 


.51 


.63 


.55 


.57 


.60 


.62 


.64 


.67 


.69 


4.7 


.47 


.99 


.52 


.54 


.56 


.59 


.61 


.63 


.66 


.68 


.70 


4.8 


.48 


.50 


.53 


.55 


.58 


.60 


.62 


.65 


.67 


.70 


.72 


4.9 


.49 


.51 


.54 


.56 


.59 


.t)l 


.64 


.66 


.69 


.71 


.73 


5.0 


.50 


.52 


.55 


.57 


.60 


.62 


.65 


.67 


.70 


.72 


.75 


5.1 


.51 


.54 


.56 


.59 


.61 


.64 


.66 


.69 


.71 


.74 


.76 


5.2 


.52 


.55 


.57 


.60 


.62 


.65 


.68 


.70 


.73 


.75 


.78 


5.3 


.53 


.56 


.58 


.61 


.64 


M 


.69 


.72 


.74 


.77 


.79 


5.4 


.54 


.57 


.59 


.62 


.65 


.67 


.70 


.73 


.76 


.78 


.81 


5.5 


.55 


.58 


.60 


.63 


.66 


.69 


.71 


.74 


.77 


.80 


.82 


5.6 


.56 


.59 


.62 


.64 


.67 


.70 


.73 


.76 


.78 


.81 


.04 


5.7 


.57 


.60 


.63 


.66 


.68 


.71 


.74 


.77 


.80 


.83 


.85 


5.8 


.68 


.61 


.64 


.67 


.70 


.72 


.75 


.78 


.81 


.84 


.87 


5.9 


.59 


.62 


.65 


.68 


.71 


.74 


.77 


.80 


.83 


.86 


.88 


6.0 


.60 


.63 


.66 


.69 


.72 


.75 


.78 


.81 


.84 


.87 


.90 



Affendix. 219 

Table VIII. Relative value tables (Continued). 



. 




Price of milk 


PER 100 


POUNDS 


, IN DOLLARS 


AND CENTS. 




3.0 


.46 


.48 


.49 


.51 


.52 


.54 


.55 


.57 


.58 


.60 


3.1 


.48 


.50 


.51 


.53 


.54 


.56 


.57 


.59 


.60 


.62 


3.2 


.50 


.51 


.53 


.54 


.56 


.58 


.59 


.61 


.62 


.64 


3.3 


.51 


.58 


.54 


.56 


.58 


.59 


.61 


.63 


.64 


.66 


3.4 


.53 


.54 


.56 


.58 


.59 


.61 


.63 


.65 


.66 


.68 


3.5 


.54 


.56 


.58 


.59 


.61 


.63 


.65 


M 


.68 


.70 


3.6 


.56 


.58 


.59 


.61 


.63 


.65 


.67 


.68 


.70 


.72 


3.7 


.57 


.59 


.61 


.63 


.65 


.67 


.68 


.70 


.72 


.74 


3.8 


.59 


.61 


.63 


.65 


.66 


.68 


.70 


.72 


.74 


.76 


3.9 


.60 


.62 


.64 


.66 


.68 


.70 


.72 


.74 


.76 


.78 


4.0 


.62 


.64 


.66 


.68 


.70 


.72 


.74 


.76 


.78 


.80 


4.1 


.64 


.66 


.68 


.70 


.72 


.74 


.76 


.78 


.80 


.82 


4.2 


.65 


.67 


.69 


.71 


.73 


.76 


.78 


.80 


.82 


.84 


4.3 


.67 


.69 


.71 


.73 


.75 


.77 


.80 


.82 


.84 


.86 


4.4 


.68 


.70 


.73 


.75 


.77 


.79 


.81 


.84 


.86 


.88 


4.5 


.70 


.72 


.74 


.76 


.79 


.81 


.83 


.85 


.88 


.90 


4.6 


.71 


.74 


.76 


.78 


.80 


.83 


.85 


.87 


.90 


.92 


4.7 


.73 


.75 


.78 


.80 


.82 


.85 


.87 


.89 


.92 


.94 


4.8 


.74 


.77 


.79 


.82 


.84 


.86 


.89 


.91 


.94 


.96 


4.9 


.76 


.78 


.81 


.83 


.86 


.88 


.91 


.93 


.96 


.98 


5 


.77 


.80 


.82 


.85 


.87 


.90 


.92 


.95 


.97 


1.00 


5.1 


.79 


.82 


.84 


.87 


.89 


.92 


.94 


.97 


.99 


1.02 


5.2 


.81 


.83 


.86 


.88 


.91 


.94 


.96 


.99 


1.01 


1.04 


5.3 


.83 


.85 


.87 


.90 


.93 


.95 


.98 


1. 01 


1.03 


1.06 


5.4 


.84 


.86 


.89 


.92 


.91 


.97 


1.00 


1.03 


1.05 


1.08 


5.5 


.85 


.88 


.91 


.93 


.96 


.99 


1.02 


1.04 


1.07 


1.10 


5.6 


.87 


.90 


.92 


.95 


.98 


1.01 


1.04 


1.06 


1.09 


1.12 


5.7 


.88 


.91 


.94 


.97 


1.00 


1.03 


1.05 


1.08 


1.11 


1.14 


5.8 


.90 


.93 


.96 


.99 


1.01 


1.04 


1.07 


1.10 


1.13 


1.16 


5.9 


.91 


.94 


.97 


1.00 


1.03 


1.06 


1.09 


1.12 


1.15 


1.18 


6.0 


.93 


.96 


.99 


1.02 


1.05 


1.08 


1.11 


1.14 


1.17 


1.20 



220 Testing Milk and Its Products. 

TaWe VIII. Relative value tables [Continued). 



0. . 




Price 


OF MILK PER 100 POUNDS, IN DOLLARS AND CENTS. 


3.0 


.61 


.63 


.64 


.66 


.67 


.69 


.70 


.72 


.73 


.75 


3.1 


.64 


.65 


.67 


.68 


.70 


.71 


.73 


.74 


.76 


.78 


3.2 


.66 


.67 


.69 


.70 


.72 


.74 


.75 


.77 


.78 


.80 


3.3 


.68 


.69 


.71 


.73 


.74 


.76 


.78 


.79 


.81 


.83 


3.4 


.70 


.71 


.73 


.75 


.76 


.78 


.80 


.82 


.83 


.85 


3.5 


.72 


.73 


.75 


.77 


.79 


.80 


.82 


.84 


.86 


.88 


3.6 


.74 


.76 


. / / 


.79 


.81 


.83 


85 


.86 


.88 


.90 


3.7 


.76 


.78 


.80 


.81 


.83 


.85 


.87 


.89 


.91 


.93 


3.8 


.78 


.80 


.82 


.84 


.85 


.87 


.89 


.91 


.93 


.95 


3.9 


.80 


.82 


.84 


.86 


.88 


.90 


.92 


.94 


.96 


.98 


4.0 


.82 


.84 


.86 


.88 


.90 


.92 


.94 


.96 


.98 


1.00 


4.1 


.84 


.86 


.88 


.90 


.92 


.94 


.96 


.98 


1.00 


1.03 


4.2 


.86 


.88 


.90 


.92 


.94 


.97 


.99 


1.01 


1.03 


1.05 


4.3 


.88 


.90 


.92 


.95 


.97 


.99 


1.01 


1.03 


1.05 


1.08 


4.4 


.90 


.92 


.95 


.97 


.99 


1.01 


1.03 


1.06 


1.08 


1.10 


4.5 


.92 


.94 


.97 


.99 


1.01 


1.03 


1.06 


1.08 


1.10 


1.13 


4.6 


.94 


.97 


.99 


1.01 


1.03 


1.06 


1.08 


1.10 


1.13 


1.15 


4.7 


.96 


.99 


1.01 


1.03 


1 06 


1.08 


1.10 


1.13 


1.15 


1.18 


4.8 


.98 


1.01 


1.03 


1.06 


1.08 


1.10 


1.13 


1.15 


1.18 


1.20 


4.9 


1.00 


1.03 


1.05 


1.08 


1.10 


1.13 


1.15 


1.18 


1.20 


1.23 


5.0 


1.02 


1.05 


1 07 


1.10 


1.12 


1.15 


1.18 


1.20 


1.23 


1.25 


5.1 


1.05 


1.07 


1.10 


1.12 


1.15 


1.17 


1.20 


1.22 


1.25 


1.27 


5.2 


1.07 


1.09 


1.12 


1.14 


1.17 


1.20 


1.22 


1.25 


1.27 


1.30 


5.3 


1.09 


1.11 


1.14 


1.17 


1.19 


1.22 


1.25 


1.27 


1.30 


1.32 


5.4 


1.11 


1.13 


1.16 


1.19 


1.21 


1.24 


1.27 


1.30 


1.32 


1.35 


5.5 


1.13 


1.15 


1.18 


1.21 


1.24 


1.26 


1.29 


1.32 


1.35 


1.38 


5.6 


1.15 


1.18 


1.20 


1.23 


1.26 


1.29 


1.32 


1.34 


1.37 


1.40 


5.7 


1.17 


1.20 


1.23 


1.25 


1.28 


1.31 


1.34 


1.37 


1.39 


1.43 


5.8 


1.19 


1.22 


1.25 


1.28 


1.30 


1.33 


1.36 


1.39 


1.42 


1.45 


5.9 


1.21 


1.24 


1.27 


1.30 


1.33 


1.36 


1.39 


1.42 


1.45 


1.48 


6.0 


1.23 


1.26 


1.29 


1.32 


1.35 


1.38 


1.41 


1.44 


1.47 


1.50 



Appendix. 
Table YIII. Relatiye value tables {Continued) 



221 





Price of milk per ]00 pounds, in dollars and 


CENTS. 


3.0 


.76 


.78 


.79 


.81 


.82 


.84 


.85 


.87 


.88 


.90 


3.1 


.79 


.81 


.82 


84 


.85 


.87 


.88 


.90 


.91 


.93 


3.2 


.82 


.83 


.85 


.86 


.88 


.90 


.91 


.93 


.94 


.96 


3.3 


.84 


.86 


.87 


.89 


.91 


.92 


.94 


.96 


.97 


.99 


3.4 


.87 


.88 


.90 


.92 


.93 


.95 


.97 


.99 


1.00 


1.02 


3.5 


.89 


.91 


.93 


.94 


.96 


.98 


1.00 


1.01 


1.03 


1.05 


3.6 


.92 


.94 


.95 


.97 


.99 


1.00 


1.03 


1.04 


1.06 


1.08 


3.7 


.94 


.96 


.98 


1.00 


1.02 


1.03 


1.05 


1.07 


1.09 


1.11 


3.8 


.97 


.99 


1.01 


1.03 


1.04 


1.06 


1.08 


1.10 


1.12 


1.14 


3.9 


.99 


1.01 


1.03 


1.05 


1.07 


1.09 


1.11 


1.13 


1.15 


1.17 


4.0 


1.02 


1.04 


1.06 


1.08 


1.10 


1.12 


1.14 


1.16 


1.18 


1.20 


4.1 


1.05 


1.07 


1.09 


1.11 


1.13 


1.15 


1.17 


1.19 


1.21 


1.23 


4.2 


1.07 


1.09 


1.11 


1.13 


1.15 


1.18 


1.20 


1.22 


1.24 


1.26 


4.3 


1.10 


1.12 


1.14 


1.16 


1.18 


1.20 


1.23 


1.25 


1.27 


1.29 


4.4 


1.12 


1.14 


1.17 


1.19 


1.21 


1.23 


1.25 


1.28 


1.30 


1.32 


4.5 


1.15 


1.17 


1.19 


1.21 


1.24 


1.26 


1.28 


1.30 


1.33 


1.35 


4.6 


1.17 


1.20 


1.22 


1.24 


1.26 


1.29 


1.31 


1.33 


1.36 


1.38 


4.7 


1.20 


1.22 


1.25 


1.27 


1.29 


1.32 


1.34 


1.36 


1.39 


1.41 


4.8 


1.22 


1.25 


1.27 


1.30 


1.32 


1.34 


1.37 


1.39 


1.42 


1.44 


4.9 


1.25 


1.27 


1.30 


1.32 


1.35 


1.37 


1.40 


1.42 


1.45 


1.47 


5.0 


1.27 


1.30 


1.32 


1.35 


1.37 


1.40 


1.42 


1.45 


1.47 


1.50 


5.1 


1.30 


1.33 


1.35 


1.38 


1.40 


1.43 


1.45 


1.48 


1.50 


1.53 


5.2 


1.33 


1.35 


1.37 


1.40 


1.43 


1.46 


1.48 


1.51 


1.53 


1.56 


5.3 


1.35 


1.38 


1.40 


1.43 


1.46 


1.48 


1.51 


1.54 


1.56 


1.59 


5.4 


1.38 


1.40 


1.43 


1.46 


1.48 


1.51 


1.54 


1.57 


1.59 


1.62 


5.5 


1.40 


1.43 


1.46 


1.48 


1.51 


1.54 


1.57 


1.60 


1.62 


1.65 


5.6 


1.43 


1.46 


1.48 


1.51 


1.54 


1.57 


1.60 


1.62 


1.65 


1.68 


5.7 


1.45 


1.48 


1.51 


1.54 


1.57 


1.60 


1.62 


1.65 


1.68 


1.71 


5.8 


1.48 


1.51 


1.54 


1.57 


1.59 


1.62 


1.65 


1.68 


1.71 


1.74 


5.9 


1.50 


1.53 


1.56 


1.59 


1.62 


1.65 


1.68 


1.71 


1.74 


1.77 


6.0 


1.53 


1.56 


1.59 


1.62 


1.65 


1.68 


1.71 


1.74 


1.77 


1.80 



222 



Testing Milk and Its Products. 



Table IX. Butter chart, showing calculated yield of but= 
ter (in lbs.) from i to 10,000 lbs. of milk, testing 3.0 
to 5.3 per cent. (See directions for use, p. 211). 



H 


3.00 


3.10 


3.20 


3.30 


3.40 


3.50 


3.60 


3.70 


3.80 


3.90 


4.00 


4. It 


I 


Milk 


























Mlik 


lbs. 


























lbs. 


io,ono 


325 


336 


318 


360 


371 


383 


394 


406 


418 


429 


441 


452 


10, 000 


9,000 


293 


302 


313 


324 


334 


345 


! 355 


365 


376 


386 


397 


407 


9,000 


8,000 


260 


269 


278 


288 


297 


306 


316 


325 


334 


343 


353 


362 


8,000 


7,000 


228 


235 


244 


252 


260 


268 


276 


284 


293 


300 


309 


316 


7,000 


6,000 


195 


202 


209 


216 


22:^ 


230 


236 


244 


251 


257 


265 


271 


6,000 


5,000 


163 


168 


174 


180 


186 


192 


197 


203 


209 


215 


221 


226 


5,000 


4,000 


130 


134 


139 


144 


148 


163 


158 


162 


167 


172 


176 


181 


4,000 


3,0C0 


97.5 


101 


104 


108 


111 


115 


118 


122 


125 


129 


132 


136 


3,000 


2,000 


65.0 


07.2 


69.6 


72.0 


74.2 


76.6 


78.8 


81.2 


83.6 


85.8 


88.2 


90.4 


2,000 


1,000 


32.5 


33.6 


34.8 


36.0 


37.1 


38.3 


39.4 


40.6 


41.8 


43.9 


44.1 


45.2 


1,000 


900 


29.3 


30.2 


31.3 


32.4 


33.4 


34.5 


35.5 


36.5 


37.6 


38.6 


39.7 


40.7 


900 


800 


26.0 


26.9 


27.8 


28.8 


29.7 


30.6 


31.5 


32.5 


33.4 


34.3 


35.3 


36.2 


800 


700 


22.8 


23.5 


24.4 


25.2 


26.0 


26.8 


27.6 


28.4 


29.3 


30.0 


30.9 


31.6 


700 


600 


19.5 


20.2 


20.9 


21.6 


22.3 


23.0 


23.6 


24.4 


25.1 


25.7 


26.5 


27.1 


600 


500 


16.3 


16.8 


17.4 


18.0 


18.6 


19.2 


19.7 


20.3 


20.9 


21.5 


22.1 


22.6 


500 


400 


13.0 


13.4 


13.9 


14.4 


14.8 


15.3 


15.8 


16.2 


16.7 


17.2 


17.6 


18.1 


400 


300 


9.7 


10.1 


10.4 


10.8 


11.1 


11.5 


11.8 


12.2 


12.5 


12.9 


13.2 


13.6 


300 


200 


6.5 


6.7 


6.9 


7.2 


7.4 


7.6 


7.9 


8.1 


8.3 


8.6 


8.8 


9.0 


200 


100 


3.2 


3.4 


3.5 


3.6 


3.7 


3.8 


3.9 


4.1 


4.2 


4.3 


4.4 


4.5 


100 


90 


2.9 


3.0 


3.1 


3.2 


3.3 


3.4 


3.5 


3.6 


3.7 


3.8 


3.9 


4.1 


90 


80 


2.6 


2.7 


2.8 


2.9 


3.0 


3.1 


3.2 


3.3 


3.4 


3.4 


3.5 


3.6 


80 


70 


2.3 


2.3 


2.4 


2.5 


2.6 


2.7 


2.8 


2.8 


2.9 


3.0 


3.1 


3.2 


70 


60 


1.9 


2.0 


2.1 


2.2 


2.2 


2.3 


2.4 


2.4 


2.5 


2.6 


2.7 


2.7 


60 


50 


1.6 


1.7 


1.7 


1.8 


1.9 


1.9 


2.0 


2.0 


2.1 


2.2 


2.2 


2.3 


50 


40 


1.3 


1.3 


1.4 


1.4 


1.5 


1.5 


1.6 


1.6 


1.7 


1.7 


1.8 


1.8 


40 


30 


1.0 


1.0 


1.0 


1.1 


1.1 


1.2 


1.2 


1.2 


1.3 


1.3 


1.3 


1.4 


30 


20 


.6 


.7 


.7 


.7 


.7 


.8 


.8 


.8 


.8 


.9 


.9 


.9 


20 


10 


.3 


.3 


.4 


.4 


.4 


.4 


.4 


.4 


4 


.4 


.4 


.5 


10 


9 


.3 


.3 


.3 


.3 


.3 


.3 


.4 


.4 


.4 


.4 


.4 


.4 


9 


8 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.4 


.4 


8 


7 


.2 


.2 


.2 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


.3 


7 


6 


.2 


.2 


.2 


.2 


.2 


2 


.2 


2 


.3 


.3 


.3 


.3 


6 


5 


.2 


.V 


.2 


2 


.2 





.2 


.2 


2 


2 


2 


.2 


5 


4 


.1 


.1 


1 


.2 


.2 


.2 


.2 


.2 


.2 


,'■1 


.2 


.2 


4 


3 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


3 


2 
1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 

i 


2 

1 


1 

1 


3.00 


3.10 


3.20 


3.30 


3.40 


3.50 


3.60 


3.70 


3.80 


3.90 


4.00 


4.10 


J_ 



Appendix. 
Table IX. Butter chart (Continued). 



223 



1 


4.20 


4.30 


4.40 


4.50 


4.60 


4.70 


4.80 4.90 5.00 


5.10 


5.20 


5.30 


t 


Milk 














Milk 


lb3. 














. 












lbs. 


10, 000 


! 464 


476 


487 


499 


510 


522, 534 


545 


557 


568 


580 


592 


10, 000 


9, 000 


i 418[ 42a 


438 


' 449 


459 


4701 481 


491 


501 


511 


522 


533 


1 9,000 


8,000 


371 381 
325 333 


390 


399 


408 


418; 427 


436 


446 


454 


464 


' 474 


' 8, 000 


7,000 


1341 


349 


357 


' 365 374 


382 


390 


398 


406 


414 


7, 000 


6,000 


: 278i 286 


• 292 


299 


306 


! 313' 320 


327 


' 334 


341 


348 


, 355 


6,000 


5,000 


i 232 238 


244 


250 


255 


261 267 


273 


279 


284 


290 


296 


5,000 


4,000 


! 186| 190 


195 


200 


! 204 


209, 214 


218 


223 


227 


232 


237 


i 4, 000 


3,000 


1391 143 


146 


150 


153 


157 


160 


164 


167 


170 


174 


178 


; 3, 000 


2,000 


192.8 95.2 


97.4 


99.8 


102 


104 


107 


109 


111 


114 


116 


118 


1 2, 000 


1,000 


46.447.6 


48.7 


49.9 


51.0 


52.2 


53.4 


54.5 


55.7 


56.8 


58.0 


59.2 


1,000 


900 


41.842.8 


43.8 


44.9 


45.9 


47.0 


48.1 


49.1 


50.1 


51.1 


52.2 


53.3 


900 


800 


37-.l;38.1 


39.0 


39.9 


40.8 


41.8 


42.7 


43.6 


44.6 


45.4 


46.4 


47.4 


800 


700 


32.5:33.3 


34.1 


34.9 


35.7 


36.5 


37.4 


38.2 


39.0 


39.8 


40.6 


41.4 


i 700 


600 


127.8|28.6 


29.2 


29.9 


30.6 


31.3 


32.0 


32.7 


33.4 


34.1 


34.8 


35.5 


600 


500 


23.2 


23.8 


24.4 


25.0 


25.5 


26.1 


26.7 


27.3 


27.9 


28.4 


29.0 


29.6 


500 


400 


II8.6 


19.0 


19.5 


20.0 


20.4 


20.9 


21.4 


21.8 


22.3 


22.7 


23.2 


23.7 


400 


300 


13.9 


14.3 


14.6 


15.0 


15.3 


15.7 


16.0 


16.4 


16.7 


17.0 


17.4 


17.8 


300 


200 


9.3 


9.5 


9.7 


10.0 


10.2 


10.4 


10.7 


10.9 


11.1 


11.4 


11.6 


11.8 


200 


100 


4.6 


4.8 


4.9 


5.0 


5.1 


5.2| 


5.3 


5.5 


5.6 


5.7 


5.8 


5.9 


100 


90 


4.2 


4.3 


4.4 


4.5 


4.6 


4.7 


4.8 


4.9 


5.0 


5.1 


5.2 


5.3 


90 


80 


3.7 


3.8 


3.9 


4.0 


4.1 


4.2 


4.3 


4.4 


4.5 


4.5 


4.6 


4.7 


80 


70 


3.3 


3.3 


3.4 


3.5 


3.6 


3.7 


3.7 


3.8 


3.9 


4.0 


4.1 


4.1 


70 


60 


2.8 


2.9 


2.9 


3.0 


3.1 


3.1! 


3.2 


3.3 


3.3 


3.4 


3.5 


3.6 


60 


50 


2.3 


2.4 


2.4 


2.5 


2.6 


2.6: 


2.7 


2.7 


2.8 


2.8 


2.9 


3.0 


50 


40 


1.9 


1.9 


2.0 


2.0 


2.C 


2.1 


2.1 


2.2 


2.2 


2.3 


2.3 


2.4 


40 


30 


1.4 


1.4 


1.5 


1.5 


1.5 


1.6 


1.6 


1.6 


1.7 


1.7 


1.7 


1.8J 


30 


20 


.9 


1.0 


1.0 


1.0 


1.0 


1.0 


1.1 


1.1 


1.1 


1.1 


1.2 


1.2 


20 


10 


.5 


.5 


.5 


.5 


.5 


.5 

j 


.5 


.6 


.6 


.6 


.6 


.6 


10 


9 


.4 


.4 


.4 


.5 


.5 


M 


.5 


.5 


.5 


.5 


.5 


.5! 


9 


8 


.4 


.4 


.4 


.4 


.4 


A\\ .4 


.4 


.5 


.5 


.5 


. c 


8 


71 


.3 


.s 


.3 


.4 


.4 


.4,1 .4 


.4 


.4 


.4 


.4 


.4 


7 


61 


.3 


.3 


.3 


.3 


.3 


.3 .3 


.3 


.3 


.3 


.4 


.4 


6 


5[ 


.2 


.2 


.2 


.3 


.3 


M .3 


.3 


.3 


.3 


.3 


.3 


5 


4 


.2 


.2 


.2! 


.2 


.2 


.2[! .2 


.2 


.2 


2 


.2 


.2 


4 


3 


.1 


.1 


2 


.2 


.2 


.2 .2 


.2 


.2 


.2 


.2 


.2 


3 


2 


.1 


.1 


A 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


2 


1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


.1 


1 


1 i 


4.20 


1 
4.30 


4.40 


4.50 


4.60 


4.70 


4.80 


4.90 


5.00 


1 
5.IO1 


5.20 


5.30 


t 



224 



Testing Milk and Its Products, 



Table X. Overrun table, showing pounds of but= 
ter from one hundred lbs. of milk. See direc- 
tions for use, p. 170. 



Per 

cent. 

fat. 


1. 10 


1.11 


1.12 


1.13 


1.14 


1.15 


1.16 


1.17 


1.18 


1.19 


1.20 


Per 

cent, 
fat. 


3.0 


3.30 


3.33 


3.36 


3.39 


3.42 


3.45 


3.48 


3.51 


3.54 


3.57 


3.60 


3.0 


3.1 


3.41 


3.44 


3.47 


3.50 


3.53 


3.57 


3.60 


3.63 


3.66 


3.68 


3.72 


3.1 


3.2 


3.52 


3.55 


3.58 


3.62 


3.65 


3.68 


3.71 


3.74 


3.78 


3.81 


3.84 


3.2 


3.3 


3.63 


3.66 


3.70 


3.73 


3.76 


3.80 


3.83 


3.86 


3.89 


3.93 


3.96 


3.3 


3.4 


3.74 


3.77 


3.81 


3.84 


3.88 


3.91 


3.94 


3.98 


4.01 


4.05 


4.08 


3.4 


3.5 


3.85 


3.89 


3.92 


3.96 


3.99 


4.03 


4.06 


4.10 


4.13 


4.17 


4.20 


3.5 


3.6 


3.96 


4.00 


4.03 


4.07 


4.10 


4.14 


4.18 


4.21 


4.25 


4.28 


4.32 


3.6 


3.7 


4.07 


1.11 


4.14 


4.18 


4.22 


4.26 


4.29 


4.33 


4.37 


4.40 


4.44 


3.7 


3.8 


4.18 


4.22 


4.26 


4.29 


4.33 


4.37 


4.41 


4.45 


4.48 


4.52 


4.56 


3.8 


3.9 


4.29 


4.33 


4.37 


4.41 


4.45 


4.49 


4.52 


4.56 


4.60 


4.64 


4.68 


3.9 


4.0 


4.40 


4.44 


4.48 


4.52 


4.56 


4.60 


4.64 


3.68 


4.72 


4.76 


4.80 


4.0 


4.1 


4.51 


4.55 


4.59 


4.63 


4.67 


4.72 


4.76 


4.80 


4.84 


4.88 


4.92 


4.1 


4.2 


4.62 


4.66 


4.70 


4.75 


4.79 


4.83 


4.87 


4.91 


4.96 


5.00 


5.04 


4.2 


4.3 


,4.73 


4.77 


4.82 


4.86 


4.90 


4.95 


4.99 


5.03 


5.07 


5.12 


5.16 


4.3 


4.4 


4.84 


4.88 


4.93 


4.97 


5.02 


5.06 


5.10 


5.15 


5.19 


5.24 


5.28 


4.4 


4.5 


'4.95 


5.00 


5.04 


5.09 


5.13 


5.18 


5.22 


5.27 


5.31 


5.36 


5.40 


4.5 


4.6 


5.06 


5.11 


5.15 


5.20 


5.24 


5.29 


5.34 


5.38 


5.43 


5.47 


5.52 


4.6 


4.7 


5.17 


5.22 


5.26 


5.31 


0.36 


5.41 


5.45 


5.49 


5.55 


5.59 


5.64 


4.7 


4.8 


5.28 


5.33 


5.38 


5.42 


5.47 


5.52 


5.57 


5.62 


5.66 


5.71 


5.76 


4.8 


4.9 


5.39 


5.44 


5.49 


5.54 


5.59 


5.64 


5.68 


5.73 


5.78 


5.83 


5.88 


4.9 


5.0 


5.50 


5.55 


5.60 


5.65 


5.70 


5.75 


5.80 


5.85 


5.90 


5.95 


6.00 


5.0 


5.1 


5.61 


5.66 


5.71 


5.76 


5.81 


5.87 


5.92 


5.97 


6.02 


6.07 


6.12 


5.1 


5.2 


5.72 


5.77 


5.82 


5.88 


5.93 


5.98 


6.03 


6.08 


6.14 


6.19 


6.24 


5.2 


5.3 


5.83 


5.88 


5.94 


5.99 


6.04 


6.10 


6.15 


6.20 


6.25 


6.31 


6.36 


5.3 


5.4 


5.94 


5.99 


6.05 


6.10 


6.16 


6.21 


6.26 


6.32 


6.37 


6.43 


6.48 


5.4 


5.5 


6.05 


6.11 


6.16 


6.22 


6.27 


6.33 


6.38 


6.44 


6.49 


6.55 


6.60 


5.5 


5.6 


6.16 


6.22 


6.27 


6.33 


6.38 


6.44 


6.50 


6.55 


6.61 


6.66 


6.72 


5.6 


5.7 


6.27 


6.33 


6.38 


6.44 


6.50 


6.56 


6.61 


6.67 


6.73 


6.78 


6.84 


5.7 


5.8 


6.38 


6.44 


6.50 


6.55 


6.61 


6.67 


6.73 


6.79 


6.84 


6.90 


6.96 


5.8 


5.9 


6.49 


6.55 


6.61 


6.67 


6.73 


6.79 


6.84 


6.90 


6.96 


7.02 


7.08 


5.9 


6.0 


6.60 


6.66 


6.72 


6.78 


6.84 


6 . 90 


6.96 


7.02 


7.08 


7.14 


7.20 


6.0 



Affendi: 



225 



Table XI. Yield of cheese, corresponding to 2.5 to 6 percent 
of fat with lactometer readings 26 to 36. (See p. 172). 






Lactometrr degrees. 







26 


27 


28 


1 
29 30 


31 


32 


33 


34 


35 


36 




2.5 


7.28 


7.41 


7.54 


7.67' 7.81 


7.94 


8.07 


8.20 


8. S3 


8.47 


8.60 


2.5 


2.6 


7.44 


7.57 


7.70 


7.83 7.96 


8.09 


8 . 22 


8.35 


8.49 


8.62 


8.76 


2.6 


2.7 


7.59 


7.72 


7.85 


7.99 8.12 


8.25 


8.38 


8.51 


8.64 


8.77 


8.91 


2.7 


2.8 


7.74 


7.87 


8.00 


8.14 8.2; 


8.40 


8.53 


8.67 


8.80 


8.91 


9.07 


2.8 


2.9 


7.90 


8.03 


8.16 


8.30 


8.34 


8.56 


8.69 


8.82 


8.95 


9.09 


9.22 


2.9 


3.0 


8.05 


8.18 


8.31 


8.45 


8.58 


8.71 


8.81 


8.97 


9.11 


9.24 


9.37 


3.0 


3.1 


8.21 


8.34 


8.47 


8.60 


8.74 


8.87 


9.00 


9.13 


9.26 


9.39 


9.53 


3.1 


3.2 


8.36 


8.49 


8.62 


8.75 


8.89 


9.02 


9.15 


9.28 


9.42 


9.55 


9.68 


3.2 


3.3 


8.52 


8.65 


8.78 


8.91 


9.05 


9.18 


9.31 


9.44 


9.57 


9.70 


9.84 


3.3 


3.4 


8.67 


8.80 


8.93 


9.06 


9.20 


9.33 


9.46 


9.59 


9.73 


9.86 


9.99 


3.4 


3.5 


8.82 


8.96 


9.09 


9.22 


9.3o 


9.48 


9.62 


9.75 


9.88 


10.01 


10.15 


3.5 


3.6 


8.98 


9.11 


6.24 


9^37 


9.50 


9.63 


9.77 


9.90 


10.03 


10.17 


10.30 


3.6 


3.7 


9.13 


9.26 


9.39 


9.52 


9.65 


9.78 


9.92 


10.05 


10.19 


10.32 


10.46 


3.7 


3.8 


9.29 


9.42 


9.55 


9.68 


9.81 


9.94 


10.08 


10.21 


10.34 


10.48 


10.61 


3.8 


3.9 


9.44 


9.57 


9.70 


8.84 


9.97 


10.10 


10.23 


10.36 


10.50 


10.64 


10.77 


3.9 


4.0 


9.60 


9.73 


9.86 


10.00 


10.13 


10.26 


10.39 


10.53 


10.66 


10.79 


10.93 


4.0 


4.1 


9.75 


9.88 


10.02 


10.15 


10.28 


10.39 


10.54 


10.68 


10.81 


10.94 


11.08 


4.1 


4.2 


9.90 


10.03 


10.17 


10.30 


10.43 


10.57 


10.70 


10.84 


10.97 


11.10 


11.24 


4.2 


4.3 


10.06 


10.19 


10.32 


10.45 


10.58 


10.72 


10.85 


10.99 


11.12 


11.25 


11.39 


4.3 


4.4 


10.21 


10.34 


10.48 


10.61 


10.74 


10.87 


11.00 


11.14 


11.27 


11.41 


11.55 


4.4 


4.5 


10.36 


10.49 


10.63 


10.76 


10.79 


11.03 


11.16 


11.29 


11.42 


11.56 


11.70 


4.5 


4.6 


10.52 


10.65 


10.78 


10.92 


11.05 


11.18 


11.31 


11.45 


11.58 


11.71 


11.85 


4.6 


4.7 


10.67 


10.81 


10.94 


11.07 


11.20 


LI 34 


11.47 


11.60 


11.73 


11.87 


12.01 


4.7 


4.8 


10.83 


10.96 


11.09 


11.22 


11.36 


11.49 


11.62 


11.76 


11.89 


12.02 


12.16 


4.8 


4.9 


10.9- 


11.11 


11.25 


11.38 


11.51 


11.60 


11.78 


11.91 


12.04 


12.18 


12.32 


4.9 


5.0 


11.14 


11.27 


11.40 


11.54 


11.67 


11.80 


11.93 


12.07 


12.20 


12.34 


12.48 


5.0 


5.1 


11.29 


11.42 


11.55 


11.69 


11.82 


11.96 


12.09 


12 23 


12.36 


12.49 


12.63 


5.1 


5.2 


11.45 


11.58 


11.71 


11.85 


11.98 


12.11 


12.24 


12.38 


12.52 


12.66 


12.80 


5.2 


5.3 


11.60 


11.73 


11.86 


11.99 


12.13 


12.27 


12.40 


12.53 


12.67 


12.71 


12.85 


5.3 


5.4 


11.76 


11.89 


12.02 


12.16 


12.29 


12.42 


12.55 


12.69 


12.83 


12.97 


13.01 


5.4 


5.5 


11.91 


12.04 


12.17 


12.31 


12.44 


12.5812.71 


12.85 


12.99 


13.12 


13.25 


5.5 


5.6 


12.07 


12.20 


12.33 


12.47 


12.60 


12.73 


12.87 


13.00 


13.14 


13.28 


13.41 


5.6 


5.7 


12.22 


12.35 


12.48 


12.52 


12.75 


12.89 


13.02 


13.16 


13.30 


13.44 


13.57 


5.7 


5.8 


12.38 


12.51 


12.64 


12.77 


12.91 


13.05 


13.18 


13.31 


13.45 


13.59 


13.72 


5.8 


5.9 


12.53 


12.66 


11.79 


12.93 


13.06 


13.19 


13.33 13.47ll3.60'i3.74 


13.87 


5.9 


6.0 


12.69 


12.82 


12.95 


12.09 


13.22 


13.35 


13.49 


13.62 


13.75 


13.89 


14.02 


6.0 



226 



Testing Milk and Its Prodiccts. 



Table XII. Comparisons of Farenheit and centigrade 
(Celsius) thermometer scales. 



Fahren- 


Centi- 


Fahren- 


Centi- 


Fahren- 


Centi- 


heit. 


grade. 


heit. 


grade. 


heit. 


grade. 


+ 212 


+ 100 


+ 176 


+ 80 


+ 140 


+ 60 


211 


99.44 


175 


79.44 


139 


59.44 


210 


98.89 


174 


78.89 


138 


58.89 


209 


98.33 


173 


78.33 


137 


58.33 


208 


97.78 


172 


77.78 


136 


57.78 


207 


97.22 


171 


77.22 


135 


57.22 


206 


96.67 


170 


76.67 


154 


56.67 


205 


96.11 


169 


76.11 


153 


56.11 


204 


95.55 


168 


75.55 


152 


55.55 


203 


95 


167 


75 


131 


55 


202 


94.44 


166 


74.44 


130 


54.44 


201 


93.89 


165 


73.89 


129 


53.89 


200 


93.33 


164 


72.33 


128 


53.33 


199 


92.78 


163 


72.78 


127 


52.78 


198 


92.22 


162 


71.22 


126 


52.22 


197 


91.67 


161 


71.67 


125 


51.67 


196 


91.11 


16'» 


71.11 


124 


51.11 


195 


90.55 


159 


70.55 


123 


50.55 


194 


90 


158 


70 


122 


50 


193 


89.44 


157 


69.44 


121 


49.44 


192 


88.89 


156 


68.89 


120 


48.89 


191 


88.33 


155 


68.33 


119 


48.33 


190 


87.78 


154 


67.78 


118 


47.78 


189 


87.22 


153 


67.22 


117 


47.22 


188 


86.67 


152 


66.67 


116 


46.67 


187 


86.11 


151 


66.11 


115 


46.11 


186 


85.55 


150 


65.55 


114 


45.55 


185 


85 


149 


65 


113 


45 


184 


84.44 


148 


64.44 


112 


44.44 


183 


83.89 


147 


63.89 


111 


43.89 


182 


83.33 


146 


63.33 


110 


43.33 


181 


82.78 


145 


62.78 


' 109 


42.78 


180 


82.22 


144 


62.22 


i 108 


42.22 


179 


81.67 


143 


61.67 


107 


41.67 


178 


81.11 


142 


61.11 


106 


41.11 


177 


80.55 


141 


60.55 


! 105 


40.55 



Appendix. 227 

Table XII. Comparisons of tliermometer scales {Continued) 



Fahren- 


Centi- 


Fahren- 


Centi- 


Fahren- 


Centi- 


heit. 


grade. 


heit. 


grade. 


heit. 


grade. 


+ 104 


+ 40 


+ 68 


+ 20 


+ 32 


+ 


103 


39.44 


67 


19.44 


31 


—0.55 


102 


38.89 


66 


18.89 


30 


1.11 


101 


38.33 


65 


18.33 


29 


1.67 


100 


37.78 


64 


17.78 


28 


2.22 


99 


37.22 


63 


17.22 


27 


2.78 


98 


36.67 


62 


16.67 


26 


3.33 


97 


36.11 


61 


16.11 


25 


3.89 


96 


35.55 


60 


15.55 


24 


4.44 


95 


35 


59 


15 


23 


5 


94 


34.44 


58 


14.44 


22 


5.55 


93 


33.89 


57 


13.89 


21 


6.11 


92 


33.33 


56 


13.33 


20 


6.67 


91 


32.78 


55 


12.78 


19 


7.22 


90 


32.22 


54 


12.22 


18 


7.78 


89 


31.67 


53 


11.67 


17 


8.33 


88 


31.11 


52 


11.11 


16 


8.89 


87 


30.55 


51 


10.55 


15 


9.44 


86 


30 


50 


10 


14 


10 


85 


29.44 


49 


9.44 


13 


10.55 


84 


28.89 


48 


8.89 


12 


11.11 


83 


28.33 


47 


8.33 


11 


11.67 


82 


27.78 


46 


7.78 


10 


12.22 


81 


27.22 


45 


7 22 


9 


12.78 


80 


26.67 


44 


6^67 


8 


13.33 


79 


26.11 


43 


6.11 


t 


13.89 


78 


25.55 


42 


5.55 


6 


14.44 


77 


25 


41 


5 


5 


15.00 


76 


24.44 


40 


4.44 


4 


15.55 


75 


23.89 


39 


3.89 


3 


16.11 


74 


23.33 


38 


3.33 


2 


16.67 


73 


22.78 


37 


2.78 


1 


17.22 


72 


22.22 


36 


2.22 





17.78 


71 


21.67 


35 


1.67 


—1 


18.33 


70 


21.11 


34 


1.11 


2 


18.89 


69 


20.55 


33 


0.55 


3 


19.44 



To convert deg. Fahrenheit to corresponding deg. Centigrade : 
Subtract 32, multiply difference by 5, and divide by 9. 
Example: Which degree Centigrade corresponds to 110° F.? 110 — 32 — 78; 
78 X 5 = 390 ; 390 -^ 9 = 43.33. 

To convert deg. Centigrade to corresponding deg. Fahrenheit : 
Multiply by 9, divide product by 5, and add 32 to quotient. 
Example : Which degree Fahrenheit corresponds to 95.5° C? 95.5 X 9 — 859.5; 
859.5 ^ 5 = 171 9 ; 171.9 + 32 = 203.6. 



Table XIII. Comparison of metric and customary weights and 

measures. 



Customary- 
weights and 
measures. 



1 inch 

1 foot 

1 mile 

1 square inch. 
1 square foot. 
1 square yard 

1 acre 

1 cubic inch.... 
1 cubic foot..,. 
1 cubic yard... 

1 bushel 

1 fluid ounce... 

1 quart 

1 gallon 

1 grain.. 

1 ounce (av.).. 
1 pound (av.) 



Equivalents in metric system 



2.54 centimeters. 

.3048 meter. 
1.6094 kilometers. 
6.452 sq. centimeters 
9.29 sq. decimeters. 
.836 sq. meter. 
.4047 hectare. 
16.387 c. c. 

.0283 cub. meter. 
.765 cub. meter, 
.3525 hectoliter. 
29.57 c. c. 
.9464 liter. 
3.7854 liters. 
64.8 milligrams. 
28.35 grams. 

.4536 kilogram. 



Metric weights 

and 

measures. 



1 meter 

1 meter 

1 kilometer 

1 sq. centimeter. 
1 square meter.. 
1 square meter.. 

1 hectare 

1 c. c 

1 cub. decimeter. 

1 cub. meter 

1 hectoliter 

1 c. c 

1 liter 

1 decaliter 

1 gram 

1 gram 

1 kilogram 



Equivalents in customary 
system. 



39.37 inches. 
1.0936 yards. 
.6214 mile. 
.155 sq. inch. 
10.764 sq. feet. 
1.196 sq. yards. 
2.471 acres. 
.061 cubic inch. 
61.023 cubic inches. 
35.314 cub. feet. 
2.8377 bushels. 

.0338 fluid ounce. 
1.0567 quarts. 
2.6417 quarts. 
15.43 grains. 
.035274 ounce. 
2.2046 pounds (av.) 



(228) 



Appendix, 229 

JUQQE5TI0NS regarding the organization of co= 
operative creameries and cheese factories. 

When the farmers of a neighborhood are considering the estab- 
lishment of a creamery or cheese factory, they should first of all 
make an accurate canvas of the locality to ascertain the number of 
cows that can be depended on to supply the factory with milk. 
The area which may be drawn from, will vary according to the 
kind of factory which it is desired to operate. A successful sepa- 
rator creamery will need at least 400 cows within a radius of 
four to five miles from the proposed factory.* Small cheese fac- 
tories can be operated with less milk, and gathered-cream and 
batter factories, generally cover a much larger territory than that 
mentioned. 

In all cases, however, the question of the number of cows con- 
tributing to the enterprise must be fully settled before further 
steps are taken, since this is the vital point, and one upon which 
success will largely depend. 

Methods of organization. The farmers should form their own 
organization, and not accept articles of agreement proposed by 
traveling agents. An agreement to supply milk from a stated 
number of cows should be signed by all who expect to join the 
association. When a sufficient number of cows has been pledged 
to insure the successful operation of a factory, the farmers agree- 
ing to supply milk should meet and form an organization. This 
may be done according to either of the following plans which 
have been known to give good satisfaction. 
Raising money for building and equipment. 
First.— Each member will sign an agreement to pay on or be- 
fore a given date for a certain number of shares or stock in the 

company at dollars per share; or, 

Second.— Xn elected board of directors may be authorized to 

borrow a sum of money not exceedieg thousand dollars 

on their individual responsibility, and the sum of cents, 

(usually five cents) per hundred pounds of milk received at the 
factory shall be reserved for the payment of this borrowed money. 



Bull. 56, Wisconsin experiment station. 



230 Testing Milk and Its Products. 

Constitution and by-laws of co-operative associations are 
drawn up and signed by the prospective members of the associa- 
tion as soon as possible after it has been determined to form such 
an association. As it is impossible to include in an illustration 
all the articles and rules that ma\' be found useful in each partic- 
ular instance, the following suggestions in regard to some of the 
points to be included in the documents are given as a guide only. 
It may be found advisable to modifj' them in various ways to 
meet the needs of the organization to be formed. 

After the constitution and by-laws have been drawn up and 
made plain to all the members of the association, they should be 
printed and copies distributed to all parties interested. 

CONSTITUTION 

OR 

Articles of Agreement of the Association.* 

1. The undersigned, residents within the counties of. , 

state of. , hereby agree to become members of the 

co-operative association, which is formed for the purpose of man- 
ufacturing butter or cheese from w^hole milk. 

2. The regular meetings of the association shall be held annu- 
ally on the day of the month of Special meetings 

may be called by the president, or on written request of one-third 
of the members of the association, provided three days' notice of 
such meeting is sent to all members. 

Meetings of the board of directors may be called in the same 
way, either by the president, or by any two members of the board 
of directors. 

3. The members of the association, or three of the board of 
directors, shall constitute a quorum for the transaction of busi- 
ness. 

4. The officers of the association shall include president, secre- 
tary, treasurer, one of whom is also elected manager, and these 
officers together with three other members of the association 



* The following publications have been freely used in preparing this constitu- 
tion and by-laws: Woll, Handbook f. Farmers and Dairymen; Minn, experiment 
station, bull. No. 35; Ontario Agricultural College, special bulletin, May 1897. 



Appendix. 231 

shall constitute the board of directors. Each of these six officers 
shall be elected at the annual meeting and hold office for one year, 
or until their successors have been elected and qualified. \ny va- 
cancies in the board of directors may be filled by the directors un- 
til the next annual meeting of the association. 

5. The duties of the president shall be to preside at all meet- 
ings of the association, and perform the usual duties of such pre- 
siding officers. He shall sign all drafts and documents of any 
kind relating to the business of the association, and pay all 
money which comes into his possession by virtue of his office, to 
the treasurer, taking his receipt therefor. He shall call special 
meetings of the association whenever it is deemed necessar^^ 

In the absence of the president, one of the board of directors 
shall temporarily fill the position. 

6. The secretary shall attend all business meetings of the asso- 
ciation and of the board of directors, and shall keep a careful rec- 
ord of the minutes of the meetings. He shall also give notices of 
all meetings and all appointments on committees, etc. He shall 
sign all papers issued, conduct the correspondence and general 
business of the association, and keep a correct financial account 
between the association and its members. He shall have charge 
of all property of the association, not otherwise disposed of, give 
bonds for the faithful performance of his duties, and receive such 
compensation for his services as the board of directors may deter- 
mine. 

7. The treasurer shall receive and give receipt for all money 
belonging to the association, and pa^^ out the same upon orders 
signed by the president and the secretary. He shall give such 
bonds as the board of directors may require. 

8. The board of directors shall audit the accounts of the asso- 
ciation, invests its funds, appoint agents, and determine all com- 
pensations. They shall prescribe and enforce the rules and regula- 
tions of the factory. They shall cause to be kept a record of the 
weights and tests of the milk or cream received from each patron, 
the products sold, the running expenses, etc., and shall divide 
among the patrons the money due them each month. They shall 



232 Testing Milk and Its Products. 

also make some provision for the withdrawal of any member from 
the association, aod make a report in detail to the association 
at the annual meeting. Such report shall include the gross 
amount of milk handled during the year, the receipts from pro- 
ducts sold, and all other receipts, the amount paid for milk, also 
for running expenses, and a complete statement of all other 
methods pertaining to the business association. 

9. Among the rules and regulations to be enforced by the board 
of directors may be included some or all of the following : 

a. Patrons shall furnish all the milk from all the cows promised 
at the organization of the association. 

b. Only sweet and pure milk will be accepted at the factory, 
and any tainted or sour milk milk shall be refused. 

c. The milk of each patron shall be tested at least three times 
a month. 

d. Any patron proved to be guilty of watering, skimming or 
otherwise adulterating the milk sent to the factory, or by taking 
more than 80 pounds of skim milk or whey for ever^^ 100 pounds 
of whole milk delivered to the factory, shall be fined as agreed by 
the association. 

e. A patron's premises may be inspected at any time by the 
board of directors, or their authorized agent, for the purpose of 
suggesting improvements in the methods of caring for the milk or 
the cows, in drainage and general cleanliness; or to secure sam- 
ples of the milk of his cows for examination when it is deemed 
necessary. 

10. Any changes or amendments to the by-laws or constitu- 
tion of the association must be made in writing b^^ the parties 
proposing the same, and posted prominently in a conspicuous 
place at the creamery at least two weeks previous to their being 
acted upon. Such changes to be in force must be adopted by a 
two-thirds vote of the stockholders. 

11. In voting at any annual or special meeting of the associa- 
tion, the members shall b^ entitled to one vote for each cow sup- 
plying milk to the factorj^ or for each share of the stock owned 
by them, as agreed upon. 



INDEX 



The numbers refer to pages in the book. 



Acid measures, 42. 

Acidity of cream, 104; estimation of, 106. 

Acidity of milk, cause of, 94; determina- 
tion of, 94, 195; methods of testing, 95. 

Adulteration of milk, 88; calculation of, 
90. 

Adulterated butter, 200; cheese, 203. 

Albumen 13, determination of, in milk, 
191, 193. 

Albaminoids, 13. 

Albumose, 14. 

Alkaline tablet test, 99, 

Alkaline tabs, 101). 

Amphoteric reaction of milk, 94. 

Appendix, 205. 

Artificial butter, detection of, 200. 

Ash, determination of, in butter, 198; in 
cheese, 2)3; in milk, 17, 194. 

Automatic milk scale, 121. 

Babcock test, the, 6, 2-5; Bartlett's modi- 
fication of, 63; directions for, 2t; dis- 
cussion of details, 34; for butter milk, 
74, 77; for cheese, 77; for condensed 
milk, 79; for cream, 64, 151; for skim 
milk, 74; for whey, 74, 77; glassware 
used in, 34; modificitions of, 62; scales 
for weighing cream, cheese, etc., 71; 
water to be used in, 60. 

Bartlett's modification of Babcock test, 
63. 

Beimling test, 5. 

Bi-carbonate of soda, detection of. in 
milk, 196. 

Bi-chromate of pjtash, 141. 

Board of health degrees, 83. 

Boracic acid, 195. 

Borax, 195. 

B. & W. bottle, 76. 

Butter, artificial, 13; detection of, 200. 

Butter chart, 222; use of, 168. 

Butter, chemical analysis of, 197; com- 
plete analysis in same sample, 199; 
composition of, 205; determination of 
ash, 198; casein, 198; fat, 198; water, 
197; sampling for analysis, 197; varia- 
tions in composition, 161; yield, cal- 
culation of, 160. 



Butter fat, conversion factor for, 167; 
determination of specific gravity, 200; 
volatile fatty acids, 201; expansion co- 
efficient, 33; price per pound, 174; 
table showing amounts due for, at 12 
to 25 cents per pound, 216; test and 
yield of butter, 160. 

Butter milk, Babcock test for, 74, 77; 
chemical analysis of, 197: composition 
of, 205. 

Calculation of adulteration, 90; of milk 
solids, 85; of yield of butter, 160, 167, 
169; of cheese, 171; of dividends, at 
creameries, 174; at cheese factories, 
182. 

Calibration of glassware, 43. 

Carbohydrates, 15. 

Caseia, 13; determination of, in butter, 
198; in cheese, 203; in milk, 191, 192. 

Centrifugal machines, 47. 

Chamberland filters, 14. 

Cheese, 77; calculating yield of, from 
casein and fat, 173; from fat, 171; fiom 
Folids not fat and fat, 171; composition, 
205; chemical analysis of, 202; deter- 
mination of ash, 263; casein, 203; fat, 
202; water, 202; "filled", detection of, 
203; sampling, 77; yield, calculation of, 
160, 171; yield of, and quality of milk, 
relation between, 171. 

Cheese factories, calculating dividends 
at, 182; co-operative, 185; proprietary, 
184. 

Chemical analysis of butter, 197, 199; 
butter milk, 197; cheese, 202; milk, 186; 
skim milk, 197; whey, 197. 

Cholesterin in milk, 19. 

Citric acid in milk, 19. 

Cleaning solutions for test of bottles, 39. 

Cleaning test bottles, 36; apparatus for, 
38. 

Cochran's test, 4. 

Coloring matter, foreign, in milk, de- 
tection of, 92. 

Colostrum milk, 19; composition of, 205. 

Composite samples, 134; care of, 143; 



234 



Testing Milk and Its Products. 



case for holding, 157; methods of tak- 
ing, 134; preservatives for, 140. 

Composite sampling, by use of drip 
sample, 136; one-third sample pipette, 
138; Scovell sampling tube, 136; tin 
dipper, 134. 

Composition of butter, 205; butter milk, 
205; cheese, 205; colostrum milk, 205; 
cream, 205; milk, 205; skim milk, 205; 
whey, 205. 

Condensed milk, composition of, 205; 
testing of, 79. 

Conversion factor for butter fat, 167. 

Conversion tables for thermometer 
scales, 226; for weights and measures, 
228. 

Cow, a, when to test, 123. 

Coivs, number of tests required in test- 
ing, 121. 

Cows' milk, composition of, 205. 

Cream, acidity of, 104; avoiding errors 
of measuring in testing, 67; Babcock 
test for, 154; bottles, the bulb-necked, 
68; the VVinton, 09; care in sampling, 
necessity of, 154; determination of 
acidity in, 100, 108; errors of measur- 
ing in testing, 65; separation of, in- 
fluence of temperature, 159; spaces, 
150; specific gravity, 66; testing, 64 
testing outfit, 155; testing at cream 
eries, 150; use of 5 c. c. pipette in, 71 
use of milk test bottles in, 69; test 
bottles 67; weighing in cream testing 
71; weight delivered by a 17.6 ec. pi 
pette, 66. 

Creameries, calculating dividends at 
174, 176; co-operative, 175; cream test 
ing at, 150; proprietary, 175. 

Creamery inch, 1. 

Curd test, the Wisconsin, 111. 

DeLaval's butyrometer, 8. 

Devarda's acidimeter, 99. 

Diameter of tester and speed required, 

relation between, 50. 
Dividends, calculating, at cheese 

factories, 182; at creameries, 174. 
Draining rack for test bottles, 39. 

Expansion coeflBcient for butter fat, 33. 



Failyer and Willard's test, 4. 

Farrington's alkaline tablet test, 99. 

Fat, 12; color of, an index to strength 
of acid used, 58; content, causes of 
variation in, 120; determination of, in 
butter, 198; in cheese, 202; in milk, 
190; globules, 12; influence of tem- 
perature on separation of, 59; measur- 
ing of, in cream testing, 73; in milk 
testing, 32; pounds in 1-10,000 lbs. of 
milk, testing 3 to 5.35 per cent., 212; 
speed required for complete separa- 
tion of, 48. 

Fermentation test, the, 113. 

Filled cheese, detection of, 203. 

Fjord's centrifugal cream test, 9. 

Fluorids, detection of, in milk, 195. 

Food, influence of, on quality of milk, 
131. 

Fool pipettes, 40. 

Formaline, detection of, in milk, 197. 

Frozen milk, sampling of, 24. 

Gauges of cream, 150. 

Gerber's acid-butyrometer, 7; fermenta- 
tion test, 113. 

Glassware used in the Babcock test, 34; 
calibration of, 43. 

Globulin, 14. 

Glycerides of fatty acids, 12. 

Goat cheese, 14. 

Grain feeding, heavy, influence of, on 
quality of milk, 130. 

Hand testers, 52. 

Hemi-albumose, 14. 

Herd milk, variations in, 128; ranges in 

variation, of 129. 
Hypoxanthin, 19. 

Introduction, 1. 
Iowa station test, 5. 

Lactic acid in milk, 16. 

Lactocrite, 5. 

Lactose, 15. 

Lactoc hrome, 10. 

Lactometer, the, and its application, 80; 

degrees, 81; N. Y. board of health, 83; 

Quevenne, 80; reading the, 84; time 

of taking readings, 85. 



Index. 



235 



Lecithin iu milk, 19. 
LetFmann and Beam test, 5. 
Le2:al standards for milk, 89, 206. 
Liebermann's method, 5. 

Manns' test, 96. 

Measuring fat column in testing cream, 
73; in testing milk, 32. 

Meicury, calibration with, 43; cleaning, 
44. 

Metric and customary systems of 
weights and measures, comjiarison of, 
228. 

Milk, acidity of, 94; adulteration of, 88; 
amphoteric reaction of, 94; ash, com- 
position of, 18; chemical analysis of, 
186; cholesterin in, 19; citric acid in, 
19; colostrum, 19; composition of, 11; 
table showing composition of, 205; 
composite sampling of, 134; condensed, 
79, 205; correction table for specific 
gravity of, 208; detection of preserva- 
tives in, 109; determination of acidity, 
106, 195; of ash, 194; of casein and 
albumen, 191, 192, 193; of fat, 190; of 
milk sugar, 193; of specific gravity, 
186; of water, 188, 190; fat available for 
butter in different grades of, 165; from 
cows in heat, 89; from sick cows, 89; 
from single cows, sampling of, 126; 
variations in, 116; frozen, sampling of, 
24; gases, 19; hypoxanthin, 19; lacto- 
chrome, 19; lecithin, 19; mineral com- 
ponents, 17; partially churned, sampl. 
Ing of, 21; quality of, influence of 
food, 131; of heavy grain feeding, 130; 
of pasture, 181; method of improving, 
132; samjiling, 20; scales, 124; serum, 
11; skimming, 90; solids, 11; calcula- 
tion of, 85; sour, sampling of, 23, 26; 
standards, 89, 206; sugar, 15; testing 
purity of. 111; urea, 19; watering of, 
91; watering and skimming, 91. 

Milk test, a practical, need of, 1; re- 
quirements of, 6; bottle, use of, in 
testing cream, 69; Russian, 62. 
Milk tests, Beimling (Leffmann and 
Beamj 5; Cochran, 4; DeLaval 
butyrometer, 8; Failyer and Wil- 
lard, 4; Fjord, 9; foreign, 7; Gerber 
acid-butyrometer, 8; introduction of, 



3; lactocrite, 5; Liebermann, 6; Par- 
son, 4; Patrick (Iowa station test,) 5; 
Roese-Gottlieb, 5; Schmied, 5; Short, 
4; Thoerner, 5. 
Milk testing, 26; on the farm, 116. 

N. Y. board of health lactometer, 83; 

degrees corresponding to Quevenne 

lactometer degrees, 207. 
Non-fatty milk solids, 11, 
Normal solutions, 96. 
"No-tin" test, 52. 
Nucleiu, 14. 

Oil test churn, 2, 151. 

Ohlsson test bottle, 76. 

Oleomargarine, detection of, 200; cheese, 
detection of, 203, 

One-third sampling pipette, use of, 138. 

Organization of co-operative creameries 
and cheese factories, suggestions con- 
cerning, 229. 

Overrun, 163; calculation of, 167; factors 
influencing, 163; t?ble, 224; use of, 170. 

Parson's test, 4. 

Pasture, influence of, on quality of 
milk, 131. 

Patrick's test. 5. 

Patron's dilemma, a, 146. 

Percentages, average, methods of cal- 
culation, 145; fallacy of averaging, 
144. 

Phenolphtalein, 97. 

Pipettes, 39; proper construction of 
points, 40. 

Potassium bi-cbromate, 141. 

Power testers, 53. 

Preservaline, 109; detection of, in milk, 
109. 

Preservatives, for composite samples, 
140; in milk, detection of, 196. 

Primost, 14. 

Proteose, 14. 

Quevenne lactometer, the, 80; degrees 
corresponding to scale ofN. Y. board 
of health lactometer, 207. 

Record of tests of cows, 126. 
Reichert number, 202. 
Reichert-Wollny method, 201. 



236 



Testing Milk and Its Products. 



Relative value tables. 178, 180, 218. 
Resei'voir for water in Babcock test, 61. 
Roese-Gottlieb method, 5. 
Russian milk test, the, 62. 

Salicylic acid, in milk, detection of, 
196. 

Sampling cheese, 77; milk. 20, 26; milk 
from single cows, 126. 

Schmied method, the, 5. 

Scovell sampling tube, 136. 

Serum solids, IJ. 

Short's test, 4. 

Skimming of milk, detection of, 90. 

Skimmilk, Babcock test for, 74; chemi- 
cal analysis of, 197; composition of, 
205; test bottles, 76, 77. 

Solids not fat, 11; formula for calculat- 
ing, 86; table showing, corresponding 
to 0-6 per cent, fat and 26-36 lacto- 
meter degrees, 209. 

Sour milk, sampling of, 23. 

Spice system, the, 150. 

Specific gravity, 80; cylinders, 84; in- 
fluence of temperature, 81; of butter 
fat. determination of, 200: of milk, 
determination of, 186; temperature 
correction table, 208. 

Speed required for complete separation 
of fat, 48 

Spillman's cylinder, 195. 

Steam turbine testers, 53. 

Sulfuric acid, 54; table showing strength 
of, 56; testing strength of, 54. 

Swedish acid bottles, 42. 

Swedish acid tester, 57. 

Tank for cleaning test bottles, 40. 

Test bottle?, 34; apparatus for cleaning, 
38; cleaning, 36; double-necked, 76; 
draining-rack for, 39; marking, 35; 
for cream testing, 67; for skim milk 
testing, 76, 77; rack for use in cream- 
eries and cheese factories, 139; tank 
for cleaning, 40. 



Testers, hand, 52; p .wer, 53. 

Testing cows, number of tests required 

during a period of lactation, 121. 
Testing milk and its products, 1; on the 

farm, 116. 
Test sample, siie of, 128. 
Tests of cows, record of, 126. 
Thermometer scales, comparison of, 226. 
Thoerner's method, 5. 
Total solids in milk, 11; determination 

of, 189. 

Volatile acids, 201. 

Waste acid jar, 37. 

Water, calibration with, 45; determina- 
tion of, in butter, 197; in cheese, 202; 
in milk, 183, 190; reservoir for, 61; to 
be used in the Babcock test, 60. 

Watering of milk, detection of, 91, 

Watering and skimming of milk, de- 
tection of, 91. 

Weights and measures, comparison o f 
metric and customary, 228. 

Whey, Babcock test for, 74, 77; chemical 
analysis of, 197; composition of, 205. 

Winton cream bottle, the, 69. 

Wisconsin creamery butter, summary 
of analyses, 162. 

Wisconsin curd test, the. 111. 

World's Fair breed tests, composition of 
butter from, 161. 

Yield of butter, calculation of, 160; and 
butter fat test, 160; from milk of dif- 
ferent richness, le**; table showing, 
from 1 to 10,000 lbs. of milk, testing 
3 to 5.35 per cent., 222 

Yield of cheese, calculation of, 160, 171; 
relation between, and quality of milk» 
171; table showing, corresponding to 
2.5 to 6 per cent, of fat, with lacto- 
meter readings of 26 to 36, 225. 



n \K UK 



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LIBRARY OF CONGRESS 



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